To build a homemade camper, start with a utility trailer, and make the required additions or changes in its interior to convert it into a camper. Then, install the vents and windows at the desired places, affix the insulation and wiring, and build the furnishings.
Begin building a homemade camper by making a suitable floor plan. When converting a utility trailer to a camper, ensure that it has a door with a frame. Purchase the desired number of windows and vents, and use them to mark and cut the trailer walls to the desired size.
With a wall saw, cut the openings for vents and windows. Sand the edges of the openings, position the windows and vents appropriately, and secure them using screws. Use a tube gun or exterior sealant to seal the window and vent edges.
Then, affix framing measuring 2 by 2 inches in the trailer, and stick or staple insulation between the frames. Nail plywood on the frame boards to seal the insulation. Also, screw or nail plywood or backerboard on the trailer's floor. Glue vinyl or panel carpeting over the plywood to build the camper's floor.
Install wiring inside the camper, and connect it to a junction box. This allows for lights and sockets for plugging in appliances. Additionally, install wiring for connecting a campsite plug or generator to the camper. Finally, build the furnishings, such as a table and frames for the stove, beds and refrigerator, as required.