Corrected entry: The Griswold's drive from Chicago to Wally World in Southern California. On the trip there, they "get off the highway" to stop at Memphis State and visit Debbie Griswold's sorority. Memphis is no where near the route one would take from Chicago, and would add 5 hours to the trip.
Corrected entry: When the family is leaving their house, their route to go south makes no sense. They show that their house is southeast of downtown Chicago, so to go south toward Missouri, the logical way to go is to go south on Lake Shore Drive and eventually hit the interstates (I-90 and I-55). In this scene, they show them going north through downtown Chicago and even going further north passing Wrigley Field which is 4 miles north of downtown. So they just traveled about 7 miles north through Chicago for no reason at all.
Corrected entry: The Griswold family have their car broken into and all their clothes are stolen. However, there are numerous changes of attire for the complete family, even when he sees his Dad for the first time and at the dinner table.