Almost nothing is shut down in South Dakota. No mask mandates, and some businesses seem to be taking social distancing more serious than others. We were there in June. Visited Mt Rushmore on a Monday around dinner time and it was not busy at all. Had great meals at Desperado's in Hill City (close to where you are if you're staying at the Rushmore KOA), and at Mt Rushmore Brewery and Custer Wolf in Custer. Desperado's was operating business as usual, and it was very crowded for Sat night dinner, but not for a weekday lunch. The Custer restaurants had limited capacity and more space between tables. We went to Deadwood on a Tuesday and it was less crowded, and had a late lunch at Deadwood Social Club which is above Saloon 10. Had drinks at Saloon 10 but it started getting crowded around 5:00. If you like breweries and wineries, Miner Brewing/Prairie Berry Winery are next to each other outside of Hill City and have a huge outdoor area that's really nice and not crowded.