we used to take 10' lengths of small flexible pvc pipe and stick it in the holes that run down the top of a truck bed bend it over to the other side and throw a tarp over it like a covered wagon, put a layer or two of carpet down to lay on works great and only cost the price of a new tarp from time to time. keeps you alot drier being off the ground if it rains, if its cold you need extra carpet or some pad because the air under the bed creeps thru pretty good but thats what the metal coffee can stuffed with a roll of TP and a bottle of rubbing alcohol is for poor mans space heater.