From Hwy 20 (milepost 398): Go 5 mi W on Red Rock Rd (paved).
The camp hosts were great checking us in, Jay brought us to our side which was plenty big and offered a nice patio and stayed a bit to chat. Great views and sunrises from this spot and was close enough to West Yellowstone. Only downside is we had incredibly rude neighbors for all but 1 night of the stay, but oh well.
We've stayed here a handful of times and had a good experience but this time not that great. We came for the weekend and while enjoying a Saturday afternoon, they decided our campsite needed mowed. It's not a really grassy area so we had to go inside and close windows and doors so dust wouldn't get in and it was annoyiy loud. We came here to enjoy the quiet and nice little piece of property we rented. We paid for the site and fully expected to enjoy it. The morning we were to check out an employee came by early (invading our privacy and enjoyment of the morning) to let us know they had "99 trailers coming in." Checkout time was 11:00am so we still had a few hours. We reminded them of this. Not an enjoyable time. Not sure if we'll be back.
Terrific RV park. Everything is kept so clean. Lovely shower/bathrooms and laundry. Super friendly and helpful employees. Nice camp store. The sites have nice grass and are well spaced with FHU. About a 20 minute ride to the West Yellowstone gate.