All of this may have changed or will have changed by the time you come through South Carolina, but the Waccamaw and the Pee Dee Rivers both empty into the ICW and both flooded. The Waccamaw is still in flood stage but is receding slowly.
When I brought our boat back from Georgetown on Sunday, a 20 or so mile no-wake zone (idle speed with Coast Guard, DNR and Horry County police around every bend) ran from Barefoot Landing (M253) to Bucksport Marina (M27 7). The folks in the Socasstee area, just south of the Myrtle Beach, were hit hard. The Socasstee Swing bridge was closed for nearly a week, holding up the southern migration of boats. By the way, the bridge is pronounced Soc-Ass-Tee, not So-Cass-Tee.
Between current (Waccamaw flows northward; Pee Dee flows southward) and the no-wake zone, my trip took several hours longer than normal.
We saw very little in the way of floating debri (outside the normal logs that you typically see), but that could certainly change as the Waccamaw continues to recede.
Good luck in your trip south.