Day 1:Leave Sheridan and arrive in Hill City sometime in the afternoon. Maybe go see either Mount Rushmore or Crazy Horse. Check into the HolidayInn Express.
Day 2: at 10am ride on 1880 Train in Hill City.Right next to the hotel. Eat at Subway or something for lunch. Go to Jewel Cave and Custer State park. Maybe go through needles highway.
Day 3: leave the beautiful black hills :( . and go home