RVing in a PUP takes a specific kind of mind-set. Most PUP owners I know don't consider themselves "RVers". They are campers, canoeists, hunters, etc. As such, if they spend times on internet forums, their interest takes them elsewhere. While our family currently moves on down a road in an old Class C, I still believe that a PUP is the perfect compromise of "camping" and "RVing".
I'm not full-timing, and I live on the East Coast but your topic SO intrigued me that I had to reply. I love RPGs, board games although I don't do MMO type games. Pen and paper games take up so much space I can't imagine trying to bring my games along full-time. Of course I've also played 4e D&D in the infield at a NASCAR race so maybe I'm on the right track.
Anyway, my family and I will be in San Fran the 1st week of July if you happen to be up that way. I can't wait to hear more of this adventure quest you are setting off on.
Give each kid ONE duffel bag for EVERYTHING they want to take. Mom and Dad have to play by the same rules though. This doesn't count "camp items" like sleeping bags, stove, etc. Usually when it comes to camp gear, the more money you pay, the smaller and lighter things get. Sleeping bags are a great example. Also, sleeping pads are lighter and smaller than air mattresses. One last example:
The tent- This will likely be the first item needed and the last packed. Instead of packing it back into its stuff/storage sack, put it in the trunk, on top/around/behind the other gear. This way it fits into otherwise unused space.