Question: how long does it take to go through mount rushmore?
Answer: Not counting the drive to Mt Rushmore, you should allow 1-1.5 hours to visit the memorial. The drives thru Custer State Park (Iron Horse, Wildlife Loop, Needles) can be covered in 2-3 hours, depending on how often you pull off to view the scenery. This should be doable if you have an entire afternoon.