I have gone to the Yellowstone - Grand Teton area flying, driving a car + hotels, and motorhome, a number of times. They are all different experiences.
1. Normally when you fly - rent car - hotel you get there fast and don't take as long. Last time we did that we flew to Jackson, got rental car, stayed in Colter Bay Village. Met up with about a dozen other family members. We drove up to Yellowstone from there. Great visit and we enjoyed it. Total time about 10 days. If you added Custer State Park in the Black hills you could either drive your rental car over there or fly.
2. When we drove car - hotel it. It was basically the same trip but we stayed for a few days inside Yellowstone in addition to staying in GT. We were driving from San Diego. We stopped a little on the way to and back.
3. Motorhoming on the other hand we have taken our time and visited all the surrounding areas. We also stayed at Colter Bay Village in the campground. Motorhoming to me lends itself to retirement as you can just go at your own speed. What taking the RV does in a negative way is add the possibility of repairs to the rig along the way. Some of the places we have "camped" is at the Country Coach Factory and various CAT dealers parking lots for repairs. But if you actually want to see points of interest in the US RVing is the best way to travel. Living out of a suitcase for two months is no fun.