You will have an absolute blast at that time!!!
I went this past December 16th weekend, and it was really cool. Universal has the Macy's day parade balloons all over the park. It's not a parade that happens; the big balloons themselves are just scattered through the park. Never thought in a million years I'd get a picture with the big Snoopy and Garfield balloons!
IOA has the Grinch...man, oh, man, is it cool. He's up on a stage just barking and hollering at folks, being -- well, Grinchy! His costume and makeup are truly flawless. Dr. Seuss world is decorated beautifully.
Crowds are nonexistent. We went on a Friday, and I think there may have been a couple hundred people in both parks. We had lunch at Finnegans at Universal, sat at the bar, and for an hour, we were the only people there eating. A few passerbys came in to get a drink to go, but that was it.
Now, MK is another story, but I'm sure you'll do your research if you plan to head over
