After some looking around on the internet there isn't much in the way of supermoto races in this area, there are a few in the west mostly in California. I guess racing on the east coast at least near me is mostly motocross or drag racing. MIR and Budds Creek aren't far away.
It's a little further but OVRP in NY is doing some events this year. You can also ride with NJMiniGP at NJMP on a pavement only kart track. There's also Allsports Indoor MiniGP in MD (or VA? don't quite recall). VIR is probably your best bet for area described. Also, Supermoto East Coast (they go by a different name now but you can search them by that one) did a race at Blue Diamond in DE last year. I'm hoping they do another one.