Laura Collins-Hughes travels to western North Dakota to see The Medora Musical, “a spangled summertime revue performed in an amphitheater carved into the side of a butte, with the Badlands as its backdrop. Part country music jamboree, part variety show, it’s a wholesome cousin to the loosely scripted entertainment you find at theme parks … The crowds have been coming since 1965, and when this season wraps up on Sept. 9, the producers expect attendance for 2017 to have passed 116,000.”