@Jo Lexington I am a developer and I currently have a project in Driggs. This year, Teton county moved the minimum lot size from 2.5 acres to 5 acres on the zoning for "single family". Keep that in mind if you are trying to subdivide.
I approached the county about putting a small RV park in the Valley. The code they adopted has a 40 acre minimum for 20 spots, 60 acres for 30 spots, etc. up to a minimum of 120 acres for a maximum 60 spots. On top of that, they said directly to me they don't want it and essentially said they would try to prevent it. Depending on what you would want in there, they also regulate why the occupant is there, the minimum number of days they can stay, the maximum number of days they can stay, mandated vacancy levels, etc. Keep that in mind when considering modular units.
It's an extremely beautiful area. If you are close enough to Driggs that the land is touching, you may consider an annex and have more options available.
I'm interested to hear how this goes for you and I'm happy to help wherever I can. Feel free to DM with anything.