Looks like as good a place to start as any . .
Budget is a good thing to have a clue on but I'll give you my 2c worth anyway . .
1) loose the tradesman's lid & framework, great for storage, not too comfy to sleep in!!
2) Get a flat lid made for the front toolbox, use that for tools / fuel / gas etc
3) get a (strong) flat lid made for the main body, hinged on the drivers side so the whole lid lifts. And you have ample storage in the main body of the trailer
4) put a roof top tent on the main body.
5) add chains to your tailgate, so it is supported horizontally, then you can have a kitchen "slide out" the rear, with the tailgate acting as a seat / table
6) Depending on clearance / ride height, do a spring over axle change, and you might end up with enough room for a 150mm deep water tank direckly over the axle, under the floor . .
if there's only 1, or 2 of you, and its mostly overnight stays, you should have a great time, and get change from $1000 . .
I am in process of doing most of the above, My lid is being made now, I have kept with the tradesman style, but had them made @ 15°C from vertical, so I still end up with 1050mm flat roof, for a roof top tent . .and the whole thing sits 5' high on the road, before the tent etc.
obviously clean paint etc.
Too many choices . . .