The entire area is often referred to as the Pee Dee area. US 501 can be an experience to ride on when the beach season starts up but won't be a factor in late Feb, you should have no problems. SC 41 and 34 are lightly traveled in that area. It's a flat area with some swamps and some areas of pine trees along with farmland. SC 9 to the beach is designated a state bicycle route if you decide to take a view of the ocean. If you camp, it's really just a matter of picking out the best spot. You probably won't see any gators or black bears unless you are really lucky in late Feb.

You can also use google maps to find lightly traveled roads but there is no guarantee they will be paved roads. Personally, I like to travel on unpaved backroads as long as they aren't mud pits.

Sounds like a great trip.