The only thing I can suggest is if there are any public beaches thsat would open after Memorial Day, you could hit them now while they're still closed. Lake Wallenpaupack has public accessible areas, and I didn't see anything prohibiting metal detecting on the PPL website, but it looks like there's only boat launches, no beaches per se. I don't no where you're planning to go, but I'd say to look up state parks where you're going. The PA Dept. of Natural Resources allows detecting in parks, but has rule about digging, though, so make sure you read the rules. Good luck! Curt