Thanks for the info. Our next destination after Black Hills is Thermopolis, WY which is actually the home of the world's largest mineral hot springs. They also have a bison herd in the state park and a dinosaur museum with a dig site too so when we visit my brother we get to hit a lot of unique things there already that you can also do in the Black Hills and Yellowstone areas. Not sure if I already mentioned it here or not but on our way through WY we'll pass through a neat town called Ten Sleep that has an old general store and just outside of town has a nice brewery that has yard games and some nights live music. Looks like we'll drive right through Bighorn National Forest between there and Buffalo. That will be the first time we have gone the north route to Thermopolis, we usually come in the south route which takes us through Cheyenne and Casper which will be the route we come back to Iowa through.Our kids were about the age of yours when did the family trip that included the Black Hills, and to this day the talk about going to Evan’s Plunge, which is sort of an old school mineral springs water park in Hot Springs, SD. It's been open since 1890. I went as a kid and didn't know if ours would enjoy it, but they definitely did. We hit the regular things in the area (most of which have been listed above) and particularly enjoyed Wind Cave NP, Jewel Cave National Monument, and Reptile Gardens. Enjoy!