If you decide, after careful consideration , to leave the area rather than "ride it out" please leave as early as possible. Our first evacuation several years ago was started late and we ended up making thirteen miles in three hours between Raleigh and Winston Salem. really a mad house and loads of fun, especially the part where lots of 4 wheelers ride the shoulder then pop in front of your (heavy) RV thinking you can stop on a dime.
Good luck on whatever you do.
P.S. We left Newport (near Morehead City) for Houston just in time to get into the deep stuff with Harvey. Now we have to stay near Houston for family medical reasons, can't leave and the next big one may hit our home area.