Two words to fit your needs...
Chevy Suburban
Will seat up to 8 (9 if you get an older one). Will carry more than you want to load. For just you and your son, you can sleep in it also. My last one (2005) which was one of 6 that we have owned, got 18.5 on the highway. Very comfortable and plenty of power. Will tow OK but not as good as a pickup with heavy loads. I still have an 89 4x4 that is real toughie. Straight axles and a lift kit. Just needs a big block and some Dana 60's. Will probably have it forever.
NGH