Here are some things I have found as ideas. I am just throwing some things out there. Depending on time of year and other factors could change how its fine tuned.
From Rapid City- Just over an hour drive so round up.
Spearfish canyon – has multiple waterfalls in the area. Some are right off the road and some are a hike away. There are a few things that would be cool to see that you have to hike for
- Devils bowl (I read there are three of them. Its a short hike.
- Community Caves photo
- Roughlock Falls Link for information about it
Devils Tower WY – 2 hours from Rapid City
What we could do is drive to Devils Tower first which is a 2 hour drive. It is one of those things where you go to, look, and go on. Not really a place you need to explore. Then after spending some time at the Tower head to Spearfish and Roughlock.
Right now just gathering some info to see different options.
Little Devils Tower article