I'm going to also recommend that you look into NASA, primarily for HPDE. We also conduct amateur road racing events. NASA isn't as large as SCCA, and our autocross program is next to non-existent, but I think our HPDE program is very good.
Our track weekends feature in car instruction, as well as, classroom instruction. Check out
http://www.nasaproracing.com for more info on NASA and
http://www.nasa-southeast.com.
There are other HPDE programs out there, too, like Turn One Motorsports, who operate at Carolina Motorsports Park, and Seat Time, who operate at Roebling Raod Raceway in Savannah, GA.
I don't really want this to become a NASA vs. SCCA thread, but want to point out that there are plenty of options for getting track time.