Hi Ann - We had such a wonderful time in Yellowstone and the Tetons, plus I was told many, many times that it was a good thing we weren't there in July/August as the crowds are horrendous. Thus, in September, you'll have the best of both worlds ... fewer people and gorgeous weather. I know you're going to enjoy your 5er!!
Oh, don't know if you've been to Yellowstone before, but if you have any questions, don't hesitate to PM or email me: scooter@cruzio.com. My son-in-law's cousin was a park ranger there for many years and he gave us a lot of information on what to see/do both within the park and out towards Cody which I will be more than happy to share.
