Furnished content.
(from Lumberjocks.com)
I built this classic style teardrop trailer on a 4×8 ft cargo trailer frame. I cut the sides each from a single sheet of plywood and finished them before I began any other assembly. I also cut the holes for the doors at this time. 
The bottom was a thin sheet of plywood that I sprayed a rubber undercoat on before installation. There is a 1×1 frame on top of the subfloor. There is blue foam insulation in this gap and I ran the 12 volt wiring through here for all the signal lights to keep them protected. Make sure to use a solid piece of plywood for the floor so it won't sag while you sleep. I place the sides and a bulkhead in place to begin building out the rest of the camper.
This is a good time to put down some type of flooring before any dividing walls are put in place. I used linoleum so that it was light weight and would protect the wood from any spills. I built the cabinets next. There is a set of cabinets over the head of the bed and over the foot area. The cabinets over the foot are built on the same shelf.
I chose to run a 12 volt electrical system that runs all the lights, fan, and some power outlets inside and in the galley. I added a 110 volt shore power system for the nights at a campground. This just gave power to the outlets and recharged the battery for the 12 volt system. All the wiring ran through between the roof and ceiling.
I built storage for water, a two burner cook stove and storage for the propane cylinders. The rear door frame needed to be built while the wood was clamped to the side to get the curve right.
i got the aluminum sheet for the roof from an industrial metal supplier. The cut the large roof piece and the piece for the rear door for me. after finishing up the interior, I added the side doors cabinetry and made some segmented wheel wells just because. The battery that runs the 12 volt system and a cooler are mounted on a frame on the tongue. I used some old metal crutches to make some removable tables that attached to the sides. This allowed the tables to adjust for uneven ground.
I had always wanted to build one of these but after I moved and no longer needed this frame to haul, I found the perfect chance. It is a great road trip trailer because it was light and did not require any set up when I stopped to catch some sleep.