The next day we drove from Rapid City to Cody, WY and then just a little bit past it to Buffalo Bill State Park where we had an RV space reserved. We traveled on Interstate 90 all of the way from Chicago, but about 2/3rds of the way through our travels to Cody we had to leave Interstate 90. There were several routes we could take and we chose to take the slightly longer but more scenic route over Powder River Pass and through the Bighorn National Park. It was still very cloudy, but the rain had stopped!