Dana,
There is an incredible, free camping spot in the Gros Ventre with a stellar view of the Tetons and the eclipse.
1) Take Antelope Flat Rd. (first right after blacktail butte, heading from Jackson)
2) Follow this road a few miles, take a right at 4-way intersection
3) Continue past Teton Science School
4) Should be the second left on paved road
5) Continue past 1st parking lot, big bend in river
6) Road goes uphill, park in the square lot on the right
7) Short trail from parking lot takes you to a ridge with 3 or 4 sites.
Shoot me a message if you need more beta, I've been going here for years and it's rarely used.
Enjoy the eclipse!
-Josh