Over at Slate, they have a Cold War era map that shows all the places Soviets were and weren't allowed to visit in 1955. They could, for instance, visit Nashville, Knoxville and Chattanooga, but it looks like they couldn't do it by car. They couldn't visit Memphis, but they were welcome to travel around the rest of West Tennessee. Perhaps most awesome is that they were perfectly free to visit anywhere in Mississippi they wanted.
It's a cool map, though I guess I'm not old enough to find much rhyme or reason to where the Soviets were and weren't allowed to go. Some forbidden areas look like obvious military targets, but why you'd be able to come to, say, Nashville but not see Columbia, I'm just not sure.