Shadow mountain dispersed campground is free and has quick access to Jackson. The views are spectacular (especially at the higher sites, we stayed at the top in 16.) There’s two entry points for the campsites, both are pretty rough but totally doable, we hauled our 23’ camper up the entry towards Dubois but went up and down the other way multiple times that takes you past the Mormon Row Cabins. We drove to Yellowstone South entrance from the sites through the Grand Teton National Park, was just over an hour to the Yellowstone entrance and another hour to Old Faithful or Hayden Valley depending on which direction you go in the park. Can’t recommend these sites more, simply awesome.