Devil's Tower is pretty cool as you're approaching it from Sundance, but when you get to the NP, you're really too close. Kind of like looking at the top of the Empire State Bldg. from the sidewalk right in front of it. IMO, the best part is the prairie dog village at the entrance. But its only 30 miles from Sundance, and there's a private CG with hookups maybe 100 yds. from the entrance. They used to show "Close encounters" every night on an outdoor screen.
You can hike or drive around it.