I also go to the Portland Swap Meet. I'm lucky to live within 270 miles of it.
It's a pretty large venue and has 2 area's, the fair grounds buildings and adjacent area, plus the race track Portland International Raceway (PIR), where the Indy Car race is held. They use the two pit areas and a lot of the track, itself. It's a great little track (1.9 mi), I used to race there (SCCA).
I does take at least 3 days to cover it fully but, when I go, I'm looking for something specific so, I go for one day and don't cover areas outside of my interest, like restored cars. I usually find other things, that I can't live w/o too!
My head, hands and feet, never stop moving, from open to close. I've seen things that I never thought I'd get to see and touch, too! And talk about being tired, at the end of the day!!!
http://portlandswapmeet.com/information/info.htm