I did that in the early 90s .I took 4 piano hinges and 4 sheets of 2'x6'plywood and hung them on the walls ,they fold down and hang from a chain to make 4 bunkbeds.It's setting in the yard right now full of stands and tents and everything else I need for long trips away from home.I have worn out 2 sets of tires from draging it all over the place in the past 15 years.I love it and couldn't live with out it .I have 2 gas tanks from grills on the front and a coleman gas stove and gas lights in it .