I think the I-75 part of your trip is just fine.

The real bitch is I-24 between Nashville and Chattanooga.  That's the shortest
route between Indianapolis, where I used to live, and Orlando, where I used to
vacation, but it just ain't worth it.  That is one rugged road.  That's the one
you want to stay off of while pulling your trailer.

What you want to do is take I-64 east to Lexington, Ky, then go south via I-75.
That is about 160 miles longer, but will be a much more pleasant trip for you.
Those roads are really nice to drive, with no big elevation changes that I
recall.

Dave Head

75 through that region does have mountainous areas, but IMO, they are
not that bad. Its a very heavily travelled road, so I doubt you would be
the first to take a U-Haul trailer down that route. Just make sure that
you have your car checked thoroughly by your mechanic before making the
trip.

As for alternate routes, looking at Yahoo!maps, I gathered that I-55 to
US-78 to I-20 would also get you to Atlanta, but you would be going out
of your way (and IIRC U-haul charges mileage) and it is probablly just
as hilly.

One interesting thing I noted on Yahoo!maps is that for the interstates
in GA, they also show the interstates' state highway designations (i.e.
their map shows I-95 as I-95 and also as GA-405) eventhough interstate
highways in GA are not signed with their SR designations.