There is also a KOA on Ski Hill Road between the Bar J Chuckwagon dinner show and the Jackson Hole Ski Area. I am not a KOA fan so we have never stayed there.
Over the Teton pass (see post above) in Idaho about 20 miles in the Idaho town of victor a commercial RV park.
BTW about the Bar J-
Bar J Chuckwagon
It is the best value for your money in an area that is over priced. We go there 3-4 times/year, stay at the Gros Venture CG (no hook ups) and see the Bar J.
Disclaimer- I have NO financial intrest in the Bar J. Only that you can't beat them! One summer we saw them 5 times!