We stayed at Heartland RV Park in Hermosa, SD a few years ago. If you don't mind a typical more open RV park, it's a nice park and very convenient to just about everything you'll want to see in the area. Big enough for big rigs, and plenty of space. Good pizza place within walking distance and ~20 minutes from Rapid City if you need supplies or want to go into town for dinner. We've always planned to go back, but haven't got 'round to it.

As noted above, off season is usually less crowded. We were there in late September.

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