With the (probably) eminent release of the Halloween Horror Night ticket info/schedule, if you see a rate that you could live with, I would grab it now. You can always change or cancel if something better comes along.
Personally, I have a trip starting on Halloween (not for HHN, but instead for the runDisney races that weekend) and a couple of days ago I booked the Stay More, Save More rate that is currently available. It was decent and now I know that I have a room. Fingers crossed that I can get something cheaper, but with HHN, I know that the rates could go up as well.