Mike
We like to head out that way in as early spring as possible. One time we got to Colter Bay in the Tetons on Memorial day which is when they open. Yes you can get into snow but it melts pretty quickly that time of year. We had three inches Memorial day and several other nights but the roads were in great shape by 10 AM. It is best if you can do your trip before the schools in that area get out for the summer which is typically late June. You can see more, get around faster and enjoy more wildlife not to mention it being cheaper. As stated above you don't want to do South Dakota in August especially this August. It is some big Sturgis anniversary and they are expecting even bigger crowds. Definitely would not be an enjoyable time to go. We do make reservations for out destination locations but not for the overnight travel sites. You need to be making your reservations as we speak as things fill up fast.You will be glad that you made the trip. We took my 90 year old Mom through New England for a one month trip. She had a blast and we will remember it forever. Take it from me, do it while you and they can, you will be glad you did. Enjoy
