I live in South Louisiana, and I see both all the time. The red fox borders the cypress swamps and also all in the bottom land woods that has tupelo gum, cypress, oak, pecan and just a good mixture of woods. The gray I find all over, swamps and woods. Now what is cool, is when you hunt the cypress swamp, you find high ridges where you get hardwoods growing such as oaks, and you find that red fox right there with the grays. There is hardly any pine trees where I live down at the end or you might say the beginning of I-55. We have a good WMA down here called the Marepaus swamp. Wildlife of almost anything you want to hunt.
Now a little north of me where my son lives in Livingston parish, you also find the almighty king of red fox squirrels called The Bochman red fox. It is a beautiful squirrel, and big, with white face markings and some on his paws and so forth. Another squirrel we hunt by my sons place is the Black squirrel. It is a pretty squirrel to. Now around his place is a lot of pines and you find a lot of grays to.
Now about the rarity that you mentioned PSEsniper, I find that red fox comes out a little later sometimes than the grays and I find them to be active about 2 to 3 hours before sunset. I also think he is a lot smarter and becomes very wary as the sesaon progresses. But in all color squirrel hunting, they are a very smart animal and I think it is a great sport. Been hunting them now for at least 40 years and never get bored with it. So the only places around here that I dont see them, is in the deep cypress swamps without any high ridges.
I hope this helps out, as I am just letting you know my experiences with them.
Swampchopper