Thanks westend, I haven't got back on the project yet, I tend to slow a bit after a quick turnaround trip to Texas.
I plan to wrap the walls and roof, I haven't decided if I'm going to wrap the lower sides that but I am leaning towards it. I figure it can't hurt. From what I have been reading the overlap is the key to the proper seal. I do plan on using the foam board throughout the rest of the camper, walls and roof. I think it will insulate much better. Plus I think it will make it feel much tighter, like yours.
I hope to have the lower sides built soon so I can get the main camper reattached to the floor. I'll feel much better when it is all back in one piece.