We leave from MI on US23, just a little North of you and then take I75 all the way down.
Cinci and Atlanta are probably the 2 worst stretches of the trip. My strategy for Atlanta is to stay in the middle and go with the flow of traffic. Obviously rush hour is a little worse but its also a good idea to avoid the 2AM last call time. A lot depends on your tolerance for traffic and your level of anxiety driving an RV.
If traffic is a problem you may also want to think about driving at night. The traffic is lighter and you can stop and rest in the AM.
Typically we leave around 6 AM and drive all the way to Perry GA (just South of Macon, mm135) we usually arrive around 10 or 11 and just connect what we need. The next Am we get up around 8 and head to WDW, usually arriving around 3 with a quick stop at
Walmart on the way in. We have done this trip with the RV about 6 times now and without the RV at least a dozen more.
On the way back we stop in Cleveland TN (the halfway point for us) and just plug in, as soon as everyone is up in the AM we head for home.
Since my truck has a relatively small (26 gal) fuel tank everyone gets to use the facilities on a regular basis, this makes Disneymom happy.
Let me know if you have any specific questions
Scott