If you're not too far from Warminster, PA definitely have a shot at the autox events there. Philly SCCA hosts them. I was on my way back from WV and decided to do an event there yesterday. It's at an abandoned air strip, so the asphalt has mucho levels of grip. Only problem is that due to the large number of people they only give you 4 runs - wasn't enough for me to get my fast runs clean.
I've heard that the DC region also hosts some good events, but they have about 300 people turn up at times. They also have "Pro Solo" which has two mirrored autox courses with a drag strip like christmas tree where you go head-to-head with other drivers!