We spent one night in one of the walk-in sites here. We were able to find an open site at 10 am with no reservation, although the drive-up sites looked all full. Despite a stormy night, we enjoyed this campground, with a beautiful view of the lake. It looks like sites in the lower drive-up loop are the most desirable, being right next the the lake edge. The campground is also quite close to Mt. Rushmore, which could be a pro or con.