We are flying into Denver the last week in August. Planning on doing a big loop, ending back in Denver, (plane tickets already purchased), for a three week trip. This is the main things we want to see: Mt. Rushmore, Badlands, Cody (and surrounding), Glacier National Park, Bnaff and back to Denver. Need some help with areas not to miss. Mostly interested in natural scenery and wildlife, short walks, no long hikes. Definitely want to travel Going-to-the-Sun-Road. Please give me your thoughts.