We spent the summer living out of a pickup with a low-profile camper shell. It was such fun to develop our system. DH built a sleeping platform with hinged access doors to the storage below. I made long, narrow curtains that stayed in place with Velcro and when the curtains were in use, their storage bag velcro-s onto the wall for eyeglasses and tissue storage.
Underneath the sleeping platform, DH designed storage custom-built for the containers we used for cookware and food storage as well as the camp chairs, low concert chairs and portable table. Once we knew the space, we could make decisions on what cookware and how much food to bring, helping us decide how long we could be away from the grocery stores.
My favorite find was laundry soap/softener/dryer sheets all in one dry sheet. I didn't have to deal with storing all those separate messy products. <http://www.purex.com/products/purex-3-in-1/product-performance> A sheet could be stored with the clothes in the mesh dirty clothes bag.
Our other favorite purchase was a fast-folding canopy that can be erected over a picnic table. It fits on the roof rack exactly between the bicycles when traveling. <http://www.amazon.com/Green-Foldable-Portable-Carrying-Included/dp/B000XHWW10> (on sale everywhere after the 4th of July)
Travel companions were impressed at how slick the system was and by the end of the summer we were like a well-oiled machine when it came to setting up and breaking down the camp. I even had a system of hanging beach towels between the "bookend" cab doors of the truck that served as a changing room. (Ever try changing clothes while laying 15 inches away from the ceiling?)
Everything served multiple purposes. The map bag became a grocery bag while at the store. The ice chest was spare seating at camp. Pillows cushioned items during travel. Binder clips served numerous purposes holding clothing, paperwork, tablecloths, windscreens. Only the guitar was a unitasker... :-)