We came home from Yellowstone across North Dakota back in 2014. Places we stayed overnight were:
In Billings - Yellowstone River RV Park - Paid $72 for FHU (won't stay in Billings again!)
In Miles City - Miles City KOA - Paid $38 for W/E
In Dickinson ND - North Park Campground - Paid $33 for FHU (lots of oil field worker families there at the time, but probably not so much now)
In Jamestown ND - Jamestown Campground - Paid $34 for W/E
There is also a campground with electric sites at
Fort Abraham Lincoln State Park just south of Bismark. We didn't stay there, just visited the Fort.
