Two issues come to mind. The first is that you cannot carry inside a NPS building that houses employee offices. The good news is that these have huge and obnoxious signs. The second is that you can't OC on a State Park in NC. Which would rule out Mt Mitchell, some trails around Grandfather Mtn, and Mt Jefferson around Jefferson, NC. If you are just riding the parkway it's not a big deal. There may be some I'm missing but those are the ones that come to mind. I OC around the Boone/Linville area when I am up there hiking and have not had any issues. I've run into several rangers on trails and in the front country.