I agree with bikendan about visiting after Labor day to avoid crowds, however, It can start getting cold. You can always bundle up a little though. I have visited those areas once in August, the other 3 times in September. I always head to The Tetons, then to Yellowstone, and from there to Glacier. There are a number of beautiful parks in Canada not too far from Glacier that are worth checking out also, such as Banff, and Jasper. Calgary and Edmonton are nice cities to check out also. Do a Bing search on those places to get an idea. Have a Great Trip!
Bob in Calif.
