If you mean Jan 1 to Jan 8 we have found no problem getting that for BWV boardwalk view and AKV savanna by calling about 10 1/2 months out but I would not delay much beyond that particularly for first few days of Jan. Your real crowded days depend on when Jan 1 falls. Next year it will be a Thursday and you should expect heavy booking through Sunday the 4th. When Jan 1 falls on a Sunday or Monday, booking Tuesday on should not be much problem.
If you mean night of December 31, you should call to reserve at the first opportunity (11 months out) because it goes quickly.