There is often week 51 availability at Eagles Nest, (and other Marco flex resorts) due to club members who have flex weeks and win that week in the lottery. In that case, they get 7000 points for their two bedroom flex week. Some deposit as soon as the week is assigned (12 months from check-in) in late December, if they want to push their points out a year. When Week 51 includes christmas, it's a tougher reservation but certainly worth the call 9 months out. Week 52 is a much harder reservation. And Sanibel and Captiva are tougher too.
It's also worth posting a wish or exchange for that week, no later than November the year before. Here's an example of why so early. I own a fixed week 51 at Eagles Nest. I can't use it next year but have already turned it into HGVC points because I had to do it before the end of 2011 in order to push them into 2013 -some folks like to borrow points ahead, I like to stack them up in the future.