My suggestion: Carlisle, PA.
Rent the Carlisle Fairgrounds (two options). So far on their site they have no events for July 18-20th and 25-27th. You can rent the Fairgrounds or the Expo Center. Here is the link:
http://www.carsatcarlisle.com/default.aspx
There is also a northeast version of the “Trail of the Dragon.” It is State Route 125 and here is the link:
http://www.motorcycleroads.us/roads/pa125.html It isn’t too far a drive from Carlisle, Harrisburg, Hershey.
This road is simply the best twisty road within two and one half hours drive of New York City. Bar none. It contains a number of 180 degree, mountain hairpin turns that you rarely find in this part of the country. The road contains hundreds of turns once in the mountain stretch of it. Right before the mountain twisties is a 3 mile, flat, straight dragstrip-like stretch of road -- perfect for getting the carbon out of your engine before attacking the mountain twisties. Traffic is light. This is a roller coaster ride of a road that you will never forget. It is the 'Tail of the Dragon' of the northeast. I call this my 'double black diamond' road -- it is for serious drivers only. I have never left this road without a smile on my face and my heart pumping. Wow! - Scott (9/18/09)
Pros: PA will be cooler than south for the summer for those wanting to escape the heat. Carlisle is 35-40 minutes from Hershey, PA. Carlisle and Harrisburg are inexpensive. There is an airport in Middletown (close to Harrisburg).
http://www.flyhia.com/
Cons: Further away than Virginia for those in the FL area. There really isn’t a track near here. However, you may be able to fabricate a cone course if the Fairgrounds are rented.