

Frame: 4'x10' welded frame heavy duty trailer, 15" wheels. Currently a utility trailer, plan is to strip all the wood off it the weekend of June 11. We'll be building the floor of the trailer out over the wheel wells, so ultimately it'll be ~6'x10'. Purchased frame on Craigslist, ~$600. Came with a stand jack, went to Harbor Freight and picked up a wheelie jack for ~$30 so I can move it by myself.
Walls: Will be 2" 250 rigid foam with some wood hard points built in. Estimating 8 sheet minimum of 4'x8' sheets, planning on 10 sheets in case of oops. ~$265. Not sure whether we'll be going with 2x4 or 1x2 uprights/crossbeams. No cost estimate for wood or ingredients for "The Mix" yet. The current plan is for every piece of wood involved in this build to be saturated with "The Mix".
Skin: #12 (11.5oz) cotton canvas duck, 144" width. I REALLY didn't want a seam on the roof if I could avoid it. Purchased 13 yards of it for ~$9/yd from CanvasETC. Total plus shipping came to $150.56 #12 has about an 8% shrinkage rate, but even with a 10% shrinkage rate, it should still wash up to over 120" width, so should allow me to cover the roof and walls with a single sheet.
Glue: Titebond II. In theory, 1 gallon of TBT covers 250sq ft to a depth of 6mm. Right now, I estimate a minimum of 3gal, so ~$54.
Paint: Gripper, at least 5gal. ~$100. Not sure we'll get anything other than the primer coat on it before the deadline.
Access points: The plan is to go with a commercial 68" RV door. ~$200, unless I have to buy one new, in which case the price doubles. There'll also be at least one window, also probably commercial, but we're not sure where or how big it will be just yet.
Electric: The plan is to run a 3 breaker box of 120v, for standard RV campground power. Might do a small solar panel to run fans and small lights.
Sundries: AC standalone unit, $100 from Craigslist. Eventually the camper will have a toilet, but there's some discussion whether we're going with a canister unit or Luggable Loo style composting toilet. Won't be needed until winter camping happens.
The requirements of the camper were thus:
Must be able to be towed by my Isuzu Rodeo, #3500 gvw limit on vehicle/tow package.
Must be able to fit a queen, or near queen, mattress without having to perform feats of gymnastics to enter/exit the camper.
Must be able to exit/enter the vehicle without bending or crouching.
Must be large enough to handle an AC unit.
Must have wheels and tires capable of handling highway speeds.
Druthers:
I'd like an indoor potty for winter camping. Preferably with enough space to make walls around it for some sort of privacy.
Trailer shape should eventually be similar to this.