I’ll agree with some of the above. Deadwood is a cool
Spot but with kids I wouldn’t spend much time there. Mt. Rushmore is a must see but even taking the little hike around it doesn’t take really long. There’s lots to do in Keystone/Black Hills area though. My kids really like Bear Country and Reptile Gardens. I’d recommend getting to Bear Country first thing in the morning and beating the rush. The alpine slide is fun for the kids and adults as well. We went south a little last year to Monmouth Dig site and it was really cool, the kids enjoyed it and still talk about it from time to time. I’ve always liked Devils Tower it’s a nice little walk around it. Buffalo Wyoming is a nice town to stay in for the night or Sheridan. Staying on the mountain is even better. The South Fork Lodge on the Buffalo side is a nice place.