Doug, the Race Track one is Thurs. thru Saturday, the Portland Swap meet is Friday thru Sunday (done so the cluster fu*k isn't a GIANT cluster fu*k). They are about a half mile apart.
The race track is 2 1/2 miles around with stalls on both sides of the track, all the way around, plus another 500 or so in the pit area.
The one up above (where most of the restoration vendor's are) has three massive buildings and probably another 1,000 or so outdoor spaces... all full.
In the thirty years or so that I have been going, the Sun has been out oh, lets see, three or four times at least.
Dress accordingly.......................................
Bob