Used to be stationed at Ellsworth AFB when I was in the Air Force.
Didn't see anyone mention Reptile Gardens, which used to always be a good place to take the kids. About 5-6 miles south of Rapid City on the way to Mt Rushmore.
If you have time, driving through Custer State Park is good...
Another Thorne Smith fan
Fun to find this thread about Thorne Smith, one of my all-time favorite writers.
I think Mr. Wilson was on the mark with the "It" factor regarding Night Life of the Gods.
For the record, they did make a movie out of it in 1935 but it's not available in any home...