Great information.
We are newbies at this but we did figure out that you just have to keep trying. We were there for Thanksgiving last year and we called , and called and called. Finally an openning and we snatched it up.
Then... while we were there I received an e-mail telling me I could go ahead and book for the following year. Some sort of special booking option for current, returning guest. I neglected and this year had to go through the same call, call, call process but eventually... we were successful. We will be at the Fort from Saturday to Satuday the week of TG.
I must say I'm a bit confused about how they manage reservations. This year we managed to book Monday and Tueday night only. We wanted the whole week. We called and called and called, and then when my wife called and also wanted to extend our park passes, they were able to find a spot for us for the entire week. I suspect that they probably overbook based on historical cancellations just like the airlines do.
We also met a couple last year who managed to get a site for the enitre week of Thanksgiving at the very last minute. They had been booked for the week of Christmas, then changed their minds at the last minute and got a full week at TG instead, no problem. We also found out from the same couple that many campers will book a site during highly desirable times (Christmas and TG) not knowing whether they're actually going to use the site or not. Then as the payment due date approaches, they make their final decission and either pay the balance or cancel. Explains the increase in cancellations as the Payment due date approaches.
Now all of the above is just from my observations. If anyone really understands how this bit of Disney Magic really works... Like Mickey... I'm all ears.