I'd head up to "Clyde Cooper's" in Raleigh via I-85 from Atlanta, stopping "Bucky's BBQ" in Greenville, SC on the way through SC, then stop at "Lexington BBQ" in Lexington, NC, then on to Raleigh. Return to Atlanta via I-85 to Charlotte, I-77 to Columbia, SC, and I-20 back to Atlanta, stopping at "Mac's Speed Shop BBQ" in Charlotte, "Maurice's Piggy Park" in Columbia, SC, and "Sconyer's Bar-B-Que" in Augusta, GA.
This will provide you with a gracous plenty GOOD barbecue with plenty of opportunity to try MANY different types of regional sauces:
South Carolina mustard sauce - Bucky's & Maurice's
South Carolina thick red sauce - Bucky's
South Carolina vinegar sauce - Bucky's
North Carolina thin red sauce - Lexington & Mac's Speed Shop
North Carolina vinegar pepper sauce - Clyde Cooper's
Georgia thick red sauce - hot or mild - Sconyer's
Maurice's is an experience in itself! May not be politically correct for ALL, but culturally significant for "southern" barbecue!!!
Just a thought! Whatever you do and wherever you go I'm sure you will have some good stuff and enjoy the experience!!!