We will be there too, our kids are out starting the 17th until after New Years.
We were there last year at this same time and the crowds were BIG. We just picked the things that were very important to us, and did those. We told the kids not expect to ride very many rides (we each picked one ride that we really wanted to go on and we fast passed those).
MK was the worse. We found MGM to be alright. If you an stay up late, plan to stay after the fireworks (if the park is open, last year MK was open for 1 hour after Wishes). That was the BEST hour of the day. We were able to get on the rides with little wait at that time.
We were surprised that we could just walk into the restaurant in Italy without a PS for lunch.
We had a great time, but we went in with a good attitude and decided to focus on the decorations.
This year our 'main' ride will be the Stitch ride since it is new. Then we want to see the Mermaid and Beauty and the Beast show at MGM. We plan to see the Osborne Lights at MGM for the first time (they weren't there last year). Other than that, whatever happens happens.
Have fun!
DJ