Our 2014 dates will be September 6-13.
I got great rates for us at the Dolphin, Night of Joy will be going on during that time, the park is open longer than in Nov/Dec, Mickey's Not So Scary Halloween party is going on, and both water parks will be open. And it's usually very, very low crowds that week. The drawback is the heat - mid 80's to low 90's, usually. We've never had much of a problem with rain, but there's usually a higher chance of rain during that time, and a hurricane risk (my husband would say bring it on, knowing him!).
I tried to get October for us, but hotel rates are higher that month (it's a major convention month at Disney), and crowd levels have crept up, too.
So September it is!
I'll post more information soon. I'm working with Disney to tweak a few things for our group and will open registration as soon as I can.