Hopefully this bodes well for me this coming weekend.
Experience tells me that you’re OK up until Wednesday before Thanksgiving. That’s when the bulk of guests will arrive by and they’ll stay through Sunday. That means by Monday after Thanksgiving, WDW is heading towards the lightest crowds of the year and it stays that way until Dec 16 or so and then the Christmas crowd starts to build.
As others said, MK always tends to be the most crowded park. AK will likely be closed at 5 every day, Epcot always closes at 9, except between Thanksgiving and New Year’s when they are open until 9:30. The Studios’ closing time will float all over the place. As early as 7:30 and as late as 10.
Make your dining reservations now. Decide which evening shows you want to see and which EMH and after than, be flexible with the little stuff. Look for targets of opportunity (short lines) and keep your eyes open for dropped fast passes. I found 4 Space Mountain fast passes on top of a trash can that I guess a family couldn’t use. I would have used them myself, but there was a sudden downpour and the queue emptied out so much I was able to walk around 3 times and ride with almost no wait and didn’t need the passes. So, I gave the passes to someone else.