we stayed at the KOA in west Yellowstone. It is a little further out than grizzly RV but we still did not find it too out of the way. I think we were about 20 minutes from the lower loop. The gate to the park is right there in west Yellowstone.
Others have also recommended grizzly RV. reservations are a must during the summer.
HTT: "EscapeII" 2016 Shamrock 23WS (current)
PUP: "Escape" 2010 Rockwood HW 277 (gone)
TV: "Bruce" 2011 Dodge Durango V8 Hemi Crew
Just us gals (me, Sis and our daughters)
Traveled 19520 miles and 209 nights in 7 years and counting