If you do the Glacier to Yellowstone to Teton run, I would hit Glacier first but then deviate west a bit as you go south - take 93 South of Missoula and go through Hamilton, Salmon, Stanley and Sun Valley down to 20, and then take 20/26 east to Yellowstone/Teton. It's a beautiful drive and I personally think the Sawtooths near Stanley are more impressive than the Tetons, not to mention far less crowded and developed. The Ketchum area is pretty cool too, and you can stop off at Craters of the Moon on your way over to Yellowstone/Teton. Just a thought.
