Slide in camper. Dimensions custom fit first gun tundra, probably most other 6 1/2 ft box trucks. I started this about 2 years ago and progress has ground to a halt, work and life getting in the way. The design was based off the 4 wheel campers idea. Its very light, framed in 1" aluminum. Plywood tub with roll on bed liner. Door was purchased and is super nice with screen and locks. Happy to answer any questions and provide whatever info I've gathered through the process. Also have various tools that could be handy to the person who takes this on, such as pnuematic rivet gun, TIG welder, etc... tools would be negotiated separately but I'd try to make it a deal. Would be a cool little pop up camper for someone who wants a project this winter with the bulk of the welding time already out of the way. Could definitely be finished as a hard top too.
I can provide exact dimensions to see if this will fit your rig.
