We were there THE exact dates last year. It wasn't as crowded as I thought it would be. In two days of touring, we got at least 60 rides done + Fireworks and Fantasmic. However we got to the park before opening and stayed until 10 or 11 both nights. My TR is in my sig. It's a great time to go, especially this year because my guess is that a lot of schools have the week of Christmas and the week after off, instead of the week before.
Definitely use FP a lot! It helps a ton especially with one or two days of touring. Getting there early is also another key in getting more done. Lines for major attractions don't get long until maybe 10 with an 8AM opening.
Just a note. When we went, the Wednesday was pretty empty, but by evening of Thursday the crowds began to increase. I recommend going to DL on W, and DCA with possibly a little DL on Th.
Also keep in mind that unless you are staying onsite, you won't be early entry eligible. That means if you decide to enter DL at opening on Thursday, there will already be people in line for Fantasyland rides, Nemo, Space, and Buzz. If you choose to do this, I recommend heading to the other side of the park first and doing Fantasyland, Nemo, Space, and Buzz on your previous day.