My question was what do I need back seats for, not what Dave needs back seats for.Should Dave place his children in the cooler or spare gas tank ? In our case, just the wife and I, so two seater works fine. But your Ultra 4 car wouldn't get far up in our area, unless you brought a chain saw in order to remove a number of pesky pine trees.
Are the pine trees spaced exactly 72" apart in your area? My U4 is 80" wide. Some guys with the 72" wide side by sides end up wider than that when they put bigger tires and different wheels on them, so they could be in trouble up there too. If 8" makes the firm difference between passable or not on a constant basis, I'm not thinking that's a trail I'd find all that fun no matter what vehicle I'm in.