Thanksgiving is on Thursday the 22nd so expect very long lines on Friday and Saturday. Starting on the 25th the crowds will most likely be minimal though. The Sunday after Thanksgiving is usually when people start travelling home so the rest of your trip shouldn't be busy.
We will get there on Sat. the 23rd but in the afternoon. I figured we get settled in our condo- have a nice slow paced dinner and go to Cirque du Soleil with our group. On Sunday is when the fun begins and it will be non stop til we leave the following saturday. I was told that we probably wouldn't run into very long lines but that person was guessing as to the time of year- not from experience. That's why I asked here- So many experts on actually going to the parks- not just advertising them.
Thanks!