Hehe....multiple builds ?
Mine started out to serve as a trailer for my wife and I to camp in and also serve as a fish/hunt rig for me and a buddy. I've gradually come to the realization that a smaller trailer like a TD is a better idea for hunting and fishing since all we really need is a secure place for food and a place to crash. We're usually out of camp before the sun comes up and back in pretty near dark so we don't need much and I'd prefer a smaller footprint. Being able to bury a smaller trailer in the bushes at one of my 'spots' is pretty appealing too and that's not so easy to do with a trailer that's over 7' tall and 13' long.
So, I'm about half done the outer shell and I'm already thinking about the next one, though I would be prepared to sell this one if it doesn't get used enough and keep the smaller one for me.
Then I lucked into a (free !) slipper-sprung boat trailer axle in decent shape.

And GPW, you'll appreciate this after cutting down your foam for the FS...
I got a bunch of 24"X48" dock billet (55lb foam) - 18 lineal feet of it...144 cu ft...about 8K lbs of bouyancy and about $2k MSRP...also free
Whatever I do with it, I still have to rip the foam into 2'X2' billets to store it. At this point the as-yet-undetermined craft will probably start out as a 16'X20' floating platform for a wall tent that will eventually sport a small cabin. Because we have such steep rocky shorelines here (think: fjords), floating cabins have been popular since the turn of the century. The places I like to fish have so few people that there are all kinds of floating 'squatters', but even to lease a Crown water lot it's only 500-1500/yr.

I made up a hotwire cutter using materials at hand but, after burning through a few of my wife's guitar strings, went with a sawzall with a 12" demo blade. If I keep the feed pressure low, it cuts great. If I lean on it, the blade heats up and the foam sticks in the valleys between the teeth. Still, cutting that 8' block in half lengthwise took three fully charged, (new in April) batteries...