I agree that you want to avoid I95. I26 from Columbia to I95 is getting pretty bad too. I'll give you a couple of options once you get to Columbia and you can decide. Only reason you would go through Waycross is if you take Option 1. My preference would be option 2 or 3 with a slight nudge to Option 3 because less interstate. I've been over most of these roads and they are all good roads, none just little county roads.
Option 1: I77 to end. Left on 321 until you get to 301 south. Stay on 301 until you get to 84 south. 84 is a very nice road all the way to Valdosta. Google maps use Charlotte, Ulmer SC, Jesup GA, Valdosta (7:21 / 398)
Option 2: Using google maps, use Charlotte to Waynesboro GA to Valdosta. (6:35/ 378)
Option 3: using google maps, use Charlotte to Allentown GA to Valdosta. (6:41 / 412)
If you hit Columbia with heavy traffic, make sure you get in the left lane on I20 after you cross the river since 2 miles later you will hit I26 and sometimes the traffic really backs up getting onto I26.