I live on the east side of Atlanta in Gwinnett County. We cruised in July and drove it. We had combined it (not with a land/sea package - just our own planning) with a trip to Disney World. When we got off the ship, it was very easy to walk out to our car, put our stuff in and leave. We stopped for lunch (at a REAL restaurant - not fast food), made a couple of gas and potty stops and made it home around 6:00 to 7:00.
Driving was much more convenient for us because of the combined trip, we took food for the Disney trip and didn't have to worry about packing, etc. I will tell you that I was exhausted after our week and the trip home was hard. I am a single mom and had to do all the driving. My daughter was occupied with the little TV we travel with but I was exhausted. There was a couple of times I had to tell my group to stop at a gas station so I could walk around and get some candy (sugar rush). You stay SO busy while you are cruising....and combined with our trip to Disney......that was a tough drive.
If I had my choice, with no monetary concerns, etc, I would fly. My last memory of our wonderful trip was the exhausting haul home, not a great memory.
I think you have to taylor this sort of thing to how you like to travel in general. I agree with DAve - 6 hours is okay....you start getting over that and it is a chore.