Carlisle or Nats-which is better?

I am going to my first Carlisle. I have been to Nats in the early 90s and was amazed at the swap meat there. I am lucky I can drive up and back in one day.
I grew up in Annandale. Its only a 2 hour trip each way for you to go to Carlisle. You will not be able to cover the whole thing in a single day. It can easily take a full day to see the show cars (and car corral), and depending on how fast you walk (and how closely you look for parts), it can take two or more days to cover all the vendors. Try to go both Friday and Saturday and plan to get there early. On Sunday its a ghost town by noon.