The first piece of advice I would give it to check regularly for discounts. We went back for the first time in awhile back in 2008 and were completely unaware that they had discounts (room discounts, free dining, etc.). So, we paid full price when we could have gotten the trip a lot cheaper. I always keep track of discounts through this website or mousesavers.com. Having said that, you can book now and retroactively apply a discount. So, don't wait to book until the discount comes out. But, keep your eyes open because it can save you quite a bit of money.
The second thing I would advise is to make your dining reservations as soon as you book. You can make dining reservations 180 days before the first day of your trip. I know your children are older now, but you may want to try restaurants in Epcot and those can be booked up pretty quickly. So, as soon as you know what days you are going, start thinking of what parks you'll want to do on what days. For example, I always know that day 1 we are going to the Magic Kingdom, so I know to make dining reservations at the Crystal Palace. Try and think through your trip so that you can reserve your dining conveniently. At the end of the day, though, we always get a park hopper so that we can jump from park to park if we're dining in a different park.
The third thing I would recommend is getting the Dining plan. It is much more convenient we think than paying out of pocket for meals.
Another thing I would recommend is that if you research your hotels and determine that staying in a DVC villa is best for you, don't book it directly with Disney. Rent the points from a webiste at
http://www.dvcrequest.com/. It much cheaper. Yes, you have to do everything a la carte, but you can still get it all done and may save you some money on your room. I say "may" because Disney has not released a December discount yet. It may be a room discount saving your anywhere from 15%-30% off of your room. So, when you are determining whether to rent points keep that in mind.
Being in December, you probably won't need to upgrade your ticket to a water park ticket because it will be too cold I would think??? But, that upgrade does include a "5th" park in Downtown disney which is like an indoor gaming place. It's called Disney Quest. I've never been because my kids are too young. But, if your kids like video games and such, they may like it.
Also, in December there will be special parties at the Magic Kingdom on certain nights for Christmas. The tickets for this party are an extra cost from your park tickets. But, I would highly recommend going. It is a blast and your kids will get to ride the rides with minimal lines compared to the day time. Because it is so busy in December, keep an eye out for when these tickets go on sale because they could sell out. Also, keep in mind that the Magic Kingdom closes to the general public for this party. So, if you are at the MK on a day when this party is taking place, you will be kicked out essentially at 7pm.
Hope that helps! Have fun!!
