I always thought that a long bed P/U (or just the bed) with a utility bed installed and a camper shell on top would be pretty handy. But, why not just look for a used travel trailer, 16 ft or less should do. Already equipped with toilet, fresh water tanks, waste water tanks, stove, propane, beds, refer, just about everything you could want. Pull it with a P/U and you have more storeage space. You can add storage pods on top, all kinds of options...