Michigan to Yellowstone, Tetons, Fort Robinson

A couple of suggestions - if you have to choose between Wind Cave and Jewel Cave, I’d go for Wind Cave. IMO, Crazy Horse isn’t worth it, but others feel differently. On another trip, consider a visit to Devil’s Tower, Wy. Hopefully you won’t be in the Black Hills early in the month. The Sturgis Motorcycle Rally is Aug 3rd - 12th.
For Yellowstone be sure to bring a good pair of binoculars or a camera with a big zoom lens. You’ll want them for viewing wildlife.