In that case, given the amount of time you have, I would recommend that you read Stephen Ambrose's book Undaunted Courage, buy the journals of Lewis and Clark, and take in as much of the route as you can, much of which should be in the lower elevations. There are a lot of L&C historic sites in Montana. You could venture into Idaho a bit as well. You can do things like the Beartooth Highway, Yellowstone, the Tetons, and Cody on the back end. I am sure the Montana folks can give you insight on Glacier N.P. Have fun!
