Coming in from/going too the Badlands, Sturgis might be worth a look over Deadwood, my buddy and his family found it worth a visit in their RV this past summer, lots of cool motorcycle-related stuff even away from the August HD Rally.

Bear Butte too right outside of town is interesting, in part because of the accommodations they make as this is still considered a sacred site among the Traditionalists of the local Indian Tribes. The view from near the top is worth a look. Given a choice I'd look at Devil's Tower WY as I drove by but actually stop at Sturgis/Bear Butte.

Its been years and it was only the one time but IIRC Hwy 212 between the Sturgis area and the Little Bighorn was an interesting drive if you want to skip the Devil's Tower.

If you DO drive by Devil's Tower, the enormous open pit coal mines outside of Gillete would definitely be an education.

"...if the gentlemen of Virginia shall send us a dozen of their sons, we would take great care in their education, instruct them in all we know, and make men of them." Canasatego 1744