We visited Horsethief Lake Campground after seeing Mt. Rushmore on an extended road trip back to Maine. It was a beautiful spot overlooking a little lake, set back from the main road. The star gazing above the lake is incredible, no light pollution to be found. It's the closest campground to Mt Rushmore and only has about 40 sites. Because of this I would recommend getting there as early as possible. The price ($24?) was very reasonable and there were basic ammentities such as a toilet and fresh water. Definitely would recommend this to anyone looking for a basic tent site in close proximity to Mt Rushmore.