There are lots of campgrounds in Alaska and the Yukon territory. Most of them are not fancy, and are mainly gravel with few trees and little landscaping. We had no problem getting into them in our Rushmore which is not a small rig. We didn't spend long in the campgrounds though, there is lots of exploring to do.
If anyone is planning to go I recommend the book by Mike & Terri Church, "The Guide to Alaska Camping", published by Rolling Homes Press. It gives good info on all campgrounds, the highways and attractions. This, along with "The Milepost", was invaluable to us on our recent trip.