Spent the day in Custer State Park and watched one motorhome (class C) having to turn around on a mountain road. Not fun but there was no way it was going to get thru a 8 1/2 ft wide tunnel.
Wish I'd have thought to take a picture like I did on the one below. I think he would have made it. The tunnel was about 10' W and 12 1/2' high. He was afraid to try it and cant say I blame him. He was just west (i think) of Palmer Gulch camp ground.