There's a nice FHU KOA just outside the entrance to Devil's Tower. Same folks operate the General Store next door. You're only about 30 yards from the entrance to Devil's Tower NP. Drive up to the NP office to park. There's a well marked trail around the base of the tower for a hike.
As you're driving in from Sundance to DT, there are several places to pull over and take a pic of Devil's Tower. By the time you get to the entrance, you're too close to get a decent picture. Kinda like taking a picture of the Empire State Building from the sidewalk in front of it. You're just too close.
If you go to Custer SP, be sure to drive the wildlife loop. If you have a toad, drive the Peter Norbeck Scenic drive, on Needles Hwy. but your RV is too big to get thru the one lane tunnels. There are tour busses that fit.
