I Mountain biked this a couple of years back. Along the route I only saw a couple of spots where I would have needed to be careful in the van. I saw a Subaru out there but am not sure if they were doing the whole trail or an out and back. They were about at the midpoint when I saw them.
We stayed at Murphy Hogback the first night. That was too far in but was the closest site open that night. We ended up pushing our bikes up the hill in the dark. The next night we were at Labyrinth which I liked a lot. Potato Bottom looked like a good place to camp as well.
A write up of that trip starts here if anyone is interested. I'd love to go back again at some point.