If you have your heart set on a particular resort you should book now. If you are flexible then there will be plenty for you in a few months. Theres even more flexibility if you would consider offsite. Even last minute you can get good rates offsite. If you plan to fly and/or rent a car now is the time to book that though, especially the car. Rates are going up up up for around thanksgiving. I had booked a rental car for 6 nights arriving on Thanksgiving. It was $150 a month ago when I booked it. We decided to add a day, still arriving on Thanksgiving, price nearly doubled. I booked it anyway but I would hate to see what another month brings!

Car rental reservations are not charged until you pick up the car so you can reserve and cancel last minute with no penalty.
We are also hoping for
free dining. Last year it included Thanksgiving weekend but so far this year Thanksgiving has been blocked out for all the promotions. We are just waiting it out to see what is offered, I don't mind booking offsite if I have to.