My question is....where in the hell were they going?
There's just about
one paved road in that area (that isn't in a town, anyway, and there ain't many of those, either), and they should have stayed on it if they were heading for Vegas. There isn't really much in that area worth straying from the highway to go see that I know of.
And the thing with gravel or dirt roads Nevada is, if you don't know the
current condition of the road, it's best not to drive it with anything that can get stuck easily, like a van. There's too damn many of them and very few of them are maintained very well; even the ones that are supposed to be well maintained can be washed out or deeply rutted, especially during the spring when the road crews haven't had a chance to get out to do anything with them and the ground is still soggy.
And of course, as they found out the hard way, if you do get stuck you're most likely going to be out of cell phone range, there's unlikely to be very many people around, and it could be a very, very long walk to the nearest ranch house.