It's a long fairly boring drive. South of Richmond/Petersburg, not much in terms of urban areas until Savannah, especially in South Carolina. So plan your fuel stops appropriately. (You'll be OK in Virginia and North Carolina, though.) South of It's almost all four lanes (two lanes in each direction) so it can get a bit crowded in SC at certain times. It opens to six lanes in Georgia.
Regarding road conditions, I would recommend taking I-295 around Richmond/Petersburg instead of driving through downtown. A better road and 70 MPH instead of 55/60. You'll see signs telling you the travel times just before the exit (I believe exit 84 IIRC.)
Between exits 81 (I-40) and 58 in North Carolina approaching Fayetteville, there is road construction (widening from four to eight lanes), and there have been frequent crashes that causes delays. Check Google Maps or Waze frequently. US 301 parallels I-95 for most of NC, so that's a possible bailout. There's other construction projects between exits 40-12 (also widening from four to eight lanes), but I don't think those are too far along, and shouldn't be as much of an issue. (I don't know as much about South Carolina conditions, other than the pavement's not in as good condition, or wasn't two years ago when I went from NC to Port Everglades. I think SC has started a project to rebuild the I-95/I-26 interchange, but that's a minor blip on the road for you.)
You've made a really good plan to give yourselves two+ days, so you shouldn't be too rushed.