Well, to start with, the fact that Duke chooses to continue living on his boat rather than take the apartment upstairs from the Grey Gull says something about him, if only that he's comfortable in his living conditions and prefers not to change. The boat is safe, the boat is familiar. The boat is also a means for him to escape the craziness of Haven, even if only for a little while, even if that promise of escape is more along the lines of a security blanket than anything he'd actually do. For his smuggler contacts, for whom trust and routine are important things and changes in routine signify potential threats or complications at best, keeping the boat indicates that he's keeping his old way of life at least inasmuch as he's not going to turn rat on them. Plus, I bet it makes a nice handy side business for the Gull.
So, for this first profile of the places in which our Havenites spend the bulk of their quality time, Duke Crocker's home, the Cape Rouge.
Starting with the deck. The main deck when we see it is usually covered with boxes and equipment, although concessions are made for when it's a more stationary residence in the form of strings of lights hanging and other things not likely to be prudent in an out-on-the-seas situation. In the Trial of Audrey Parker he sets it out for an evening card game, with folding chairs and table items on one of the hatches as a makeshift table. Glass containers and tea light candles, pillar candles and empty bottles are scattered around, not all of them empty bottles from the beer he and his guests have been drinking. One assumes that Duke can leave out bottles and candles since the Cape Rouge does spend most of its time at harbor, these days, which makes it doubly noteworthy that these are the things he ends up leaving out. He likes candles, he likes small sources of light rather than big spotlights, which is interesting for someone security conscious enough to leave guns everywhere, and possibly a commentary on how he prefers shadows or possibly indicating that he prefers his lights up close and personal. At least, it seems likely that he didn't bring out all those candles for that evening and that they're more permanently left out there, or at least, scattered around the boat. Since Julia's there, possibly he brought them out in a romantic attempt earlier on in the day/week/month and just left them there. Other than those details and what's certainly been brought up for the evening (i.e. the folding chairs, the bench, the cushion for the bench) the bulk of the top deck is functional equipment. And lobster traps. Lots and lots of lobster traps. There's about eight of them on deck and several more stacked on the pier next to the Cape Rouge, and while there hasn't been much in the way of indicating what Duke does on his boat in his spare time, maybe they're meant to catch lobsters for the Gull? Of course, this is shortly after he acquires the Gull, so who knows.
Going below! The stateroom/mess is (at least in The Trial of Audrey Parker 1x11) at the end of/is composed of one long hall ending in a T-junction with the right branch leading out. Or at least, that's the one that has a door that we can see; we do see Duke come in a door at the opposite side (in Business as Usual 2x11) as well as a ladder descending down on the kitchen-side of the far end of the mess. At a guess, that'd be a folding ladder that was raised when Audrey and Agent Howard Fuck You came in. Coming into the long room the first impression is that most of the pictures are probably about at Duke's eye level, and most of them seem to be neutral pictures of ships, landscapes, pencil drawings, and so on. There is a wooden fish on the wall opposite and to the left of the door in which Audrey and Agent Fuck You Howard enter (still in The Trial of Audrey Parker), hand-carved and most likely stained some sort of dark stain, walnut, perhaps. This sets the tone for all the other most likely hand-carved decorative items scattered around his walls; the man likes to decorate natural. The walls themselves aren't much embellished, there's some sort of softened industrial gray-green or blue-green paint along the walls and a warm-finished beadboard ledge about halfway up the wall going around the edge of at least the mess area. The ceiling looks like there's some beadboard-style wood panels sloping up as well, of about the same shade as that around the wall, and then visible beams that might be for support but are more likely cosmetic. Coming into the room there's a half-round table extending from one wall (that might fold down for extra space, or at least, that's how I'd do it) with a clamshell-shaped brass banker's lamp on it. On either side of the table are two benches that look they might could be used as beds in a pinch, both with dark cushions with assorted more colorful decorative pillows. Around the bench on the entrance hall side of this table and extending along the wall behind it are several maps or charts, rolled up and stacked. Above those and the bench there is a plaque of some very dark (black? black walnut?) finished wood that reads 'ahead' on a brass stamp on it, and a picture in a thick wooden frame of someone surfing, which might actually be a personal picture of Eric Balfour. Although his choice of decorations doesn't tell us much about him except that he likes warm neutrals and cool colors, the fact that he does have one personal picture out may indicate either that he doesn't like to be photographed or he doesn't have many friends (with cameras?). Typically, people take photographs either for other people to see, which is less likely since it doesn't seem that Duke entertains much in the below-decks of his boat, or for themselves to remember. By that light, there's not a lot of activities that he engages in that he'd particularly like to remember, and no people specifically, at least not on a daily basis. If he has photo albums tucked away somewhere, we don't see it. The pictures he does have hanging are things he enjoys looking at or finds beautiful, but they're not personal, not in the sense of being a history of his life. One gets the sense that most of the knickknacks he has scattered along the beadboard ledge are the same way, things he picked up because he thought they were pretty but they don't connect him to any place or person.
More beadboard along the wall and two what look like inset small bars, each anchored with a pillar towards the center to form what looks like an arch overhead. Presumably this is where he'd set up and eat dinner if he had a guest/guests over, unless they were numerous enough to set up a table above-deck. There's more pictures and what looks like at least one mask hanging from a pillar or post, hanging lanterns in a couple of places to go with the lights that extend from the wall (this place is pretty well lit!) and the bar stools on the counter-and-stove side are black leather on dark cherry or mahogany wood. Again, warm colors. Everything is warm in here, with the exception of the paint on the walls, right down to the wood screen that separates the mess from his bedroom. Speaking of which, there's a hell of a lot of wood all around the interior of this boat, floor, ceilings, everything. Whatever else he may do with the rest of the boat, his home is designed to be a place of emotional comfort as well as physical, a sanctuary. A sanctuary designed to look like a land-dwelling house, I might add. There's an extending accordion-arm lamp on the far wall from the entrance, possibly that area serves as an indoor reading nook as well since we later see that he has a number of books on low-sitting shelves on that side of the mess hall. Including The Tommyknockers, thank you, props/set department. Going back along the wall past the bar we have the steampunkiest teapot ever to steam anything, with a smaller possibly ceramic dark-glazed teapot above it. Man likes his tea.
Down even from that we have the kitchen nook. It looks like his stove is gas-powered, although there could be coils in there somewhere. Another chunk of green on the wall, this time in the form of deep green tile backsplash broken with a tile mural of a frog. Is now a good time to mention that greens, blues, and browns are also very naturalistic colors? It would be absolutely fascinating to do a comparison study of Duke's place against Nathan's place given that we've been set up for (and, in the last season, assaulted with) a comparison between Duke and Nathan, but alas that is not to be. In the kitchen area we also have a number of jars, most of them the hermetic kind, with spices and herbs or possibly loose-leaf tea mixes if he does make tea with those pots on a regular basis, what look like various kinds of grains, basically all the hallmarks of a man who does his own cooking. Probably off a menu of limited variety since there's only so much room in that kitchen and only so much storage space for tools and raw materials in the immediate area, but it's hard to say how much other storage space he has on that boat and how much he dedicates to personal purposes, so for all I know he has sacks of potatoes and apples and crates of tins elsewhere. He does have a bowl of fruit at least once (Business as Usual) and several hanging mini-hammocks full of stores. The summation is, Duke is a down to earth kind of guy who cooks his own meals and likes his living area cozy, laid back, and reminding him of the outdoors. The land-based outdoors, too, again. Finally, on the other side and back around to the hall door again, we have the iguana tank. I have no idea why the man has an iguana on his boat, if indeed he does at all. Iguanas get big and need lots of space! And temperature control! Maybe he just wishes he had an iguana.
Over to his cabin, which is as mentioned earlier past a wooden folding screen, very ornately carved. The walls of his cabin are all wood, dark when unlit by any light source from inside the room but also warm when lit within and fairly smooth and shiny, probably waxed. He has at least one light by his bed, along with a couple of paperbacks when we see it in Sarah (Ep 3x09), further going with the theory that Duke likes to curl up somewhere cozy and read in his not very copious spare time. Also on the bedside table is yet another candlestick with a red taper in it, making about the fifth or sixth we've seen in the stateroom area thus far, a beer bottle, a tumbler that might have had alcohol but possibly also water in it, a couple of assorted knickknacks I can't make out, and what looks like a picture frame. There's another wooden sculpture like thing above the pillows, possibly a sculptural shelf, but other than that we don't get much of a good look at the bedroom. It's still cozy, though, and his bed is at least a queen if not a king-sized bed, room for our tall, lanky Duke to spread out.
Most to all of the areas that don't involve living quarters, on the other hand, aren't decorated at all. Cardboard boxes stacked on top of metal boxes, plastic boxes stacked as well and, of course, the requisite guns hidden freaking everywhere. So far we've seen him pull two handguns and a couple of shotguns, possibly a rifle out of various containers and inset boxes, one handgun came from under a table. I'd make some comment about him being paranoid, but the reason we know he has all of these guns stashed all over the place (along with boathooks on the walls and a sword above the door) is because he's had to pull them out to use them at one point or another. The lights are industrial, a lot of them in wire cages. Notably, the hold also has some beadboarding on the ceiling of the hold, too, so that might predate Duke's decorating or the bulk of his decorating might be the knickknacks and not the wood elements of the mess and his cabin. There are beams, too, so either the wooden beams in the mess are support beams or Duke retooled the aesthetic when he first got the boat, because there's considerably more visible aging and less care with the beams in the hold than in the mess. It's remotely possible that the woodwork is from Simon, since Simon's tastes might subconsciously affect Duke's aesthetic sense, and we do know he had the Cape Rouge and at least modified it somewhat before passing it to Sal who passed it to Duke.
One modification Duke definitely made (because he said so! in The Trial of Audrey Parker); tunnels and trapdoors everywhere. There's one in the hold to the corridor next to it and one in the mess that appears to lead under the bridge, which seems to put the bridge over the stateroom/Duke's cabin, confirmed in Business as Usual. There's a chart room what looks like it might be under the bridge as well, or possibly above the hold on the opposite end of the ship. At least one of the hatches on the deck seems to lead directly to the bilge, where Simon Crocker stashed the larger Crocker box.
And therein lies the biggest problem with untangling the Cape Rouge. There's little enough space that Duke seems to be making his own, restricting himself to two rooms as far as personalization and day to day living comfort goes, so that restricts the amount of data we have in the first place. But furthermore, given that we know the Cape Rouge was previously owned by Simon and long enough for him to leave messages and things for Duke hidden so well that Duke didn't find them for ten years. So what parts of the ship are Duke and what parts are left over from Simon? Can we safely assume that the stateroom and Duke's cabin are decorated and stocked according to his choices, or was the paneling and paint job Simon's quiet attempt to make the boat a home for the son he never treated as well as he should have, so that he wouldn't reject that convoluted gift? Poor Duke, finding out that his father essentially set up and gave him the home he's been living in for over ten years must have been a shock. And yet, he still didn't change a thing. So, it seems like a safe assumption that the Cape Rouge is set up exactly as Duke wants it, a small zone of warmth, nature, and comfort in the crazyass town that is Haven.