If you can get a body on frame rear wheel drive van with sufficient ratings, that's a good option. In the days before 4 door pickups became common, it was they typical family tow vehicle for RVs. But be careful when looking at vans, a lot of them have switched to unibody and a few full size are even front wheel drive. The other issues is payload. Those kids get bigger and 5 people can easily push 700-900lb. Add in 1200-1500 for hitch weight and all that empty space in the back of the van, it's easy to go over payload limits before you hit the tow limits.
Really the big 4 door pickups can handle 3 adults reasonably comfortably in the back seat. Gone are the days of the kids sprawling around the back of the van. As long as the dogs are crate trained, staying in the bed with a cap should work fine. Now it's easy to find a truck that can handle both the payload and tow rating.
