I love the back roads route down there. I never tried it put if I ever go down there again those are the routes I would take. Longer, but getting there would be much more fun than just screaming down 75.
I hope you are going down for the social aspect of deals gap. If so that will be a great weekend. If your going for the riding that is probably the last weekend I would go down there. It will be crowded. Lots of slow tourists.
I'd also recomend a track day if you are going down for just the sport riding. Scenery isn't as beutfull, but the riding is better. And sometimes cheaper.
02 919 (RIP)