Sorry to hear that you live in Southern Delaware. But at least, you got OC in May and October, Harrington in June and no sales taxes.
Why not bring all that money you are saving on sales taxes and come up to Carlisle. Fall Carlisle is just around the corner (first week of October). I'd go, if I weren't going to the Southeast Nats in Tampa.

I've lived in this region all of my life, and other than Hershey, Carlisle and a few national events held locally, I do not recall many swap meets taking place. Other than those mentioned previously I have found that GG Charlotte and the Turkey Run in Daytona, are some of the best on this coast.