We have been several years for xmas. It is always busy xmas day and xmas eve. So make your PS for those days ahead of time. I would avoid MK on xmas day as they are the busiest park and will fill to capacity first.
We always take the crowds in stride and try to plan something different that day not just a day at the park. One year we slept in, opened gifts and then did a resort tour. Another year we went to DisneyQuest, which was pretty empty.
Suggestions:
Take your holiday spirit with you. Maybe because it is so crowded I have seen guest behave the worst on xmas day for some reason. So be flexible, realize there will be crowds but you will still have a good time. The transportation will be busy so it may take a little more time.
You can walk over to MK from CR which is very convenient. Buses depart from the front of the resort to get to some of the other parks as well.
Attend the Flag Ceromony and Tree lighting at MK in Town Sq. It occurs everyday at 5pm. You also might consider dong the CP dinner pkg. Head over to GF and sit in the lobby eating gingerbread and enjoying the band playing xmas carols. Santa will visit each resort on xmas morning. Tour the camper loops at FW and see the amazing decorations guest put up. Think about a small tree for your room or order one ahead of time.
Overall you will find the holidays at WDW extra magical. Have a wonderful time.
