All Myrtle Beach area restaurants are casual with the exception of about 4.
Most restaurants will be open Thanksgiving Day, but I don't know if they will all be serving traditional Thanksgiving dinners. The Sun News usually publishes a list each year each year, and when I see it, I'll post it on the board.
In the meantime, here are some suggestions and hopefully others will add to this:
California Dreaming Restaurant and Bar (Surfside)
www.californiadreamings.com/Conch Cafe (Garden City)
www.conchcafe.net/Ryan's (they will have Thanksgiving on their buffet)
8671 HIGHWAY 17 BYPASS
SURFSIDE BEACH, SC 29575
Phone: (843) 215-0878
http://www.ryans.com/Texas Roadhouse (Garden City)
http://www.texasroadhouse.com/Salt Water Creek Cafe (Murrells Inlet)
www.saltwatercreekcafe.com/Any of the Marshwalk Restaurants: (Murrells Inlet)
http://marshwalk.com