We just returned from Tetons/Yellowstone, mostly Tetons. There is a gravel road that runs through the middle of the Teton Valley that you can get on. It runs along a ridge above the Snake River and we saw no other people on it. Our grandson was with us and he loves 4-wheeling. This is not a 4x4 road, but at least you can see wildlife and the area without lots of other tourists around. Next day, we found another gravel road on the East side of the valley and had some water crossings. The grandson thought that was way cool. But any of the roads that go up into the Tetons, in the park area, are only hiking or horse. As far as Yellowstone, we only had one day and did the southern circle tourist thing. Awesome country! We are definitely going back when we have more time to explore.