I would say any place with a light population, mild weather, and plenty of high quality water.
That pretty much matches the Florida panhandle. There are a huge number of natural springs, both large and small. Most of it is well above sea level.
You can get by with only a small amount of food for a pretty long time but having bad water will make you sick quick.
The writer of the book Civil War 2 mentions an area he calls the 'Dothan (Ala) Pensacola (Fla) Corridor' as a desirable place to be in a Civil War.
I'm not far from there and plan to look around in that area for a 'spot' of refuge in the near future.
I believe that the book Alas Babylon was set near the FL Panhandle. Springs were one of the benefits of surviving the aftermath of the nuclear fallout described in the book. Good choice.
That’s my plan. Plant a garden, get some livestock, and know thy neighbors.