Here's a (long-ish) video about the changes I have made to my Honda Element, Nemo, to make it into a camper.
Links to references made in the video:
ursaminorvehicles.com
sugru.com
http://www.elementownersclub.com/forums/showthread.php?t=130081 (shows detailed plans for building the boxes)
dolphinpumpusa.com
This has been a fantastic car, and I'm grateful to a lot of people for helping to make it happen. Good luck to you as you figure out how to get outside more!