Looking for suggestions of family activities during Spearfish and Mount Rushmore vacation in July

I am taking my 3 kids (ages 12, 9, and 7) on a trip this summer to South Dakota. We'll be flying in to Rapid City on the afternoon of 7/3 and renting a Suburban with a 32' travel trailer RV to stay in from 7/3 - 7/10.

We'll be staying at the Spearfish KOA Holiday from 7/3 - 7/6 and then the Mount Rushmore KOA Resort from 7/6 - 7/10.

I think I have the itinerary for 7/3 - 7/6 pretty well set...

7/3 - Arrive at Spearfish KOA in the later afternoon and set up camp.
7/4 - July 4th parade, festivities, and lunch somewhere before heading to the Black Hills Roundup rodeo (3:00 PM in Belle Fourche). See fireworks somewhere. Stay at Spearfish KOA.
7/5 - Go do the walking tour of Deadwood and see the Deadwood Alive gun fights and kids card game. Head to Devils Tower that afternoon to hike and do stargazing (there will be a new moon that night). Stay at Spearfish KOA.
7/6 - Pack up camp and drive to the Mount Rushmore KOA, stopping at Spearfish Falls along the way.

The only questions I really have on those days are...

  • Where is the best place to do July 4th morning festivities (parade, lunch, etc.) before heading to the rodeo?
  • Where is the best place to go see July 4th fireworks that night?
  • Any other suggestions of things I should see on the drive from the Spearfish KOA to the Mount Rushmore KOA, keeping in mind that I'll be driving a Suburban towing a 32' travel trailer.

My bigger question is for suggestions in setting my itinerary for 7/6 - 7/10 near the Mount Rushmore KOA. The activities I'm looking into are...

  • Mount Rushmore and Crazy Horse monuments and museums, obviously. I've read that both of those don't really take too long, especially with kids. I'm thinking I can probably knock those out early in the morning on one of my days to beat the crowds (my kids are early risers like me).
  • Cave tour at either Jewel Cave or Wind Cave. Which one would be better to do with kids of these ages?
  • Horseback trail ride. They have this available right at the Mount Rushmore KOA, but is there somewhere better nearby?
  • UTV rental. Again, this is available right at the Mount Rushmore KOA, but is there somewhere better neaby?
  • Wildlife Loop Road / Needles Highway / Iron Mountain Road. The kids will probably only be good for one or two scenic drives, and preferably if they are on the way to something else.
  • Hot Springs. Any suggestions? Or is this something I should just skip?
  • Sylvan Lake canoeing and swimming. We have tons of lake near our home in Florida that we go to all the time, but I'm thinking this will be quite a bit different, maybe?

In my current plan, we will be getting into the Mount Rushmore KOA in the early afternoon of 7/6 and departing pretty early on 7/10, so we only really have 3.5 days to fit stuff in there. Also, I want to leave some non-scheduled downtime here and there for the kids to just enjoy the activities at the KOA Resort.

Any suggestions are appreciated!