Back in the early 70's I was going to buy a Travelall. It was a 3/4 ton with the big 6 bolt pattern. My long term plan was to convert it to Chevy 8 lug axles and eventually a Chevy engine and trans along with integral power steering.
The beauty of it was it had a divorced transfer case and engine swaps out of any 2wd would be a bolt in.
Lots of guys back then put 500 Caddy engines and 455 Olds engines in Travelalls and made tow monsters out of them.
Every vehicle I ever owned, I modified to some extent, so if you look at all the vehicles and modification expenses, I would have been money ahead with the Travelall because I ended up in a Suburban!
With an 11 year old who will grow, why bother buying a multitude of vehicles? Go big and spend the money you would have spent on vehicles on your family and trip expenses. My kids remember the trips, not the toys, not the clothes, not even Disneyland stands above the camping and road trips.
Some guys here on Expo go amazing places in a full size, or van. Some even towing a trailer.