Wow! Lots of great advice on this board!
We're plotting out going from Chattanooga, TN to Yellowstone, our highlight of our trip.
Yellowstone - How long should we stay?
We're not the glance-around types of travellers. We went to Glacier NP years ago for a week. We stayed 3 nights on the west side, 4 nights on the east side. We ventured away from the park from there on 3 different days, but we enjoyed.
On this trip, we're planning to be gone 3 weeks, maybe a few days more, going thru South Dakota. I figure we will have no problem filling 3 weeks between here & there.