Factual error: During the St. Louis part, they show the Griswolds crossing the bridge into Missouri and *then* getting lost in what they title "East St. Louis." East St. Louis is actually in Illinois, so they would have encountered it before crossing the bridge. This has apparently been corrected in the video version.
Factual error: After they leave Dodge City, Ellen says they should stay on US-50. US-50 in Kansas is not a 4 lane, divided highway. In the same scene, as Christie Brinkley approaches in her Ferrari, there are mountains visible in the background. There would be no mountains visible anywhere in Kansas.
Factual error: When driving across the bridge entering St Louis, if you look in the rear windows of the car, High Rise buildings are shown. There are no buildings like these in East St Louis. If you're driving from Illinois to St Louis there would be NO buildings in the rear window.
Factual error: The whole movie he drives without any valid license plate. Just a crooked colored plate from the auto store. He would have been pulled over for that immediately, and the car probably would be impounded. Then when he does get pulled over for the leash, the cop says nothing about invalid plates. But he asks for registration proof and Clark shows it, even though he has no legal plates. Plus his meaningless plate is crooked, which is also illegal.
Suggested correction: The first 30 days after you purchase a new car you don't need plates.
Any place I've lived has required at least temporary plates before the car is actually registered.
The officer still would have to run the VIN numbers to make sure the car isn't stolen. A long time ago certain states wouldn't give you a temporary plate at all, you would only have the dealership plate on the back of the car which would raise any suspicion of law enforcement if they were to get behind you, but no ticket would be issued as long as the car is within 30 days and not stolen.
Factual error: As the family is pulling into Coolidge, KS, mountains are visible in the background. Kansas doesn't have mountains.