The characters pass by Mammy's Cupboard, a restaurant that looks like a giant southern African-American woman. It is seen soon after the characters leave the Canada-Minnesota border. In reality, the restaurant is located near the opposite end of highway 61, in southern Mississippi.
In one shot the car is traveling in the wrong direction. Before they cross the border into the USA, they cross a river on a bridge. The river must be flowing east towards Lake Superior, so the camera is also pointed east. But the car is traveling from right to left, which means it must be traveling north, not south.