Sorry it took so long for me to respond. Since most of us live in western, PA I'm not too sure that too many people will be able to help you out in the area of specific location to find copperheads. Heck, if we were going there to find them, we'd have to ask someond ourselves most likely.
Anyway, as far as the differences....Northerns are MUCH smaller than the southern variety. They are maroon with purple saddles. Extremely dark...of course they have a copper head.
The southerns get larger as well as brighter. The colors are more of a pink and orange.