If you are going to the FL panhandle your route as you are thinking may be the best. But if you are headed down into central and south FL you may want to move a bit east. I haven't been to liking much of I -65 at all. Rather rough once south of Tennessee.
Have you considered running down to Nashville then taking I-24 over to Chattanooga, then I-75 south to Calhoun (north of Atlanta).Then bypass Atlanta to the west and reconnect with 75 at Tifton, GA
Southbound out of of Chattanooga on I-75 exit 312 SW on to GA 53. Head to Rome and turn left onto GA 1 the Rome bypass. Go to US 411 and turn right and proceed to US 27. Take it south to LaGrange and turn left on to the Davis road bypass (this bypass new and it may not show on your GPS). Proceed to GA 109 (at the LaGrange mall) and turn left and proceed to I-85. Proceed north toward Atlanta about 1,000 feet on I-85 then exit immediately south on I-185 to Columbus. As you pass through Columbus you will approach the entrance to Ft Benning which you will recognize as a very ornate bridge. As you pass under that bridge exit right on to US 82/GA 520. Proceed to Tifton (using the Albany bypass) and return southbound to I-75. You will not run into traffic in GA on this route.
We run this route consistently with our moho and toad. About 80% of it is 65 mph the remainder mostly 55 except in a few short urban areas. Its scenic, relaxing and an enjoyable ride compared to the Atlanta traffic, road surface and construction mess.
Just offering this if you were headed into central and south FL.
Safe travels!