Measure your truck to ensure you purchase the right size plans for your pickup. Also determine the towing capacity of your truck by consulting your owner's manual. When you find the towing capacity, factor in the extras that will be added to the camper later, such as camping gear, food and human cargo. Because of that, don't plan to build a camper that maxes out your towing capacity with the "dry weight," or empty weight of your camper. Once you've determined the size and weight you can haul, purchase your plans and study them carefully.
Buy your camper materials, and ensure you have the right tools to do the work. For a quality slide-in camper, you'll need fiberglass or aluminum siding, plywood, lumber, industrial glue, windows, doors, various screws and other hardware. Follow your camper plans carefully to make sure you get the right materials. You'll also need at least some basic carpentry tools, such as a drill, saw, level and measuring tape.
Build the frame. You'll begin this process by cutting your floor piece, attaching it to your side and front walls, and then installing ceiling joists. Your back wall will consist mostly of a door opening with two small framed walls on either side. Since you are going to take your camper on and off your pickup, you'll want a solid frame before moving on.
Put insulation and siding in place. Some basic truck campers use plywood as siding to save money; for a slide-on slide-off model, however, you'll probably want to go with the lightest materials possible. Fiberglass or aluminum siding is ideal for this job, depending on the specifics of your camper plans. As you install siding, leave room for your vents, windows and the door.
Install your vents, door and window, caulking around each opening to make it weatherproof.
Install molding on the corners of the camper. Caulk the corners, and cover them with aluminum molding.
Install electrical and water components to the camper, including lighting, electricity, cooking gas and water. Get help from a professional electrician if you're not confident working with wiring.
Put interior features in place, including beds, tables, sink, storage areas, flooring and curtains.
