I made the trip from Bridge Bay to Devil's Tower in 2005, We left Bridge Bay early to beat the traffic at the east entrance construction and was sitting waitingon our turn at 8am. Made a quick stop for groceries in Cody then took Hwy 16 over the Bighorns. We arrived in Buffalo about 5pm for a night at the KOA. Next morning, we still had about 2.5 hours drive to Devil's Tower. We spent about 4 hours there before making Custer around 6pm. Don't think I would like driving straight through to Devil's Tower in one day, much less trying to stop and see anything.
Distance over the Bighorns takes longer than maps suggest because going up its 30-35 mph because of the grade, then down it's about the same because you need to down shift to have brakes at the bottom.
If you are into history, I would suggest the battlefield. Would also try to add a day in between to give time to see some things.
The bighorns were wonderful driving through them, but after being in Yellowstone, they didn't seem near as grandeur as they would be coming from the east. Especially with only doing a drive-through.
