The Mason Dixon line forms parts of boundaries of 4 states: WV, PA, MD, and DE. I think the closest resorts would be Lakeview in Morgantown, WV, Lakewood in McHenry, MD or any of the coastal resorts of MD, DE would be the closest to the portion that is the boundary between MD and DE.
Depends on exactly where you're looking to go. It's not a small area.