If you could pick one car show to attend....

AACA Fall Hershey. You need two days minimum. If you're going for swap meet/parts, Thursday or Friday is the day to attend. Car judging is Saturday. It's big, and it is the entire spectrum from the early 1900 to the 70-80's, with a big emphasis on pre-war era.

Carlisle is the best car venue on the planet.