We go to WDW / DL every other year for Thanksgiving and to hear people talk you'd think it was the worst of the worst time to go, but my experience has been that it is not as bad as high summer and also not as bad as the week before Christmas. Just do the usual things that are recommended - go with a plan, get all your fastpasses at 60 days, book dining early, especially for your Thanksgiving meal if you're doing one of the more popular ones (though even if you miss out on that, most of the Food Courts even offer a Turkey dinner on Thanksgiving, as does ESPN club). Go early (before posted opening because they will likely open earlier), get fastpasses starting about 11, then when you run out, keep getting more as you go. Stuff you wouldn't think (Flight of Passage) even opens up from time to time when it's crowded if you are persistent. Book dessert parties if you can swing it for the night-time shows so you are guaranteed a spot without hassle - or just do those earlier or later during your trip. Easy peasy. Go and have fun.