Sad to hear the RTR got cancelled. IF you can get a route past Atlanta, I can get you a GPS route from Clemson to Atlanta but you will need a GPS as I don't have time to create a cue sheet as I am creating a bunch right now for other people and won't have the time unfortunately.
It basically goes from Clemson > Iva > Elberton > Winterville (east of Athens) then skirts to south around Athens to Watkinsville > Rutledge > Atlanta. The route into Atlanta uses the bike paths and/or the popular club ride routes though they may not be light traffic depending on the time/day.
These routes are based on touring by bike, not just making miles so there is some zig-zagging along the lesser traveled roads while taking services (cafe, CS, hotels, grocery, etc.) in to consideration. I personally would ride the entire route and in fact plan to do so, possibly in later September (stupid Wuhan virus is ruining all my plans!).
Another option though much longer is to take the Clemson route to all the way to Statesboro, GA, where you can pick up ACA's Atlantic Coast route to say St. George, GA, where you would do your own route to Perry, FL, where I have another route that would take you to Destin along/very near the coast. I rode the Gold Coast route a several years ago and it was nice.
Whatever you choose to do, have a wonderful and safe trip!
Tailwinds, John