I think people in the South are tough when it comes to heat. We did a sprint in southern Louisiana in late July last year. Although it was only a sprint, and I finished by 9:30, I was dying in the humidity. It was suffocating. I'm sure Alabama is quite the same. No wind, true, but the humidity was torture (but the post race gumbo was quite a different treat than what I'm used to around here ).
If you relocate to OK, and are doing Route 66 (heck- blow off the wedding and send a nice gift instead), I'd love to hang out with you. If it makes your decision any easier: we have an all you can drink post race beer truck, tons of food, and the craziest RD you'll ever meet.