OP here:

Just to circle back for anyone going to Yellowstone after Labor Day. We were there the week after Labor Day.

All camps taking reservations in Yellowstone were totally full. All first come, first serve camps were full by 8:00 AM. If you are planning on camping, I'd get reservations.

Beartooth Pass was great! Wyoming is very pretty with some beautiful country and great roads for bikes. I wish we would have had more time.