I would book as soon as you know for sure you are going. That is a really busy week, so rooms fill up fast. If you want to be someplace specific, and it looks like you are, then you need to book it. Don't worry about waiting for any discounts to come out...you can apply them to your standing reservation at a later date. I always book way out..long before my trip. Just once did I book a trip at the 30 day mark but it was the first week in Dec so not that many people were there, filling up the place.