I stayed at the Gaylord Texan in November. My first impression was the resort is huge! Room location is critical, so when you check in, make sure your room is near the elevators and facing into the atrium. Overall great stay. If by any chance you're a golfer, Cowboys is next door and a great place to play! Enjoy!
You are probably going at the right time. For the past 4 years, i have taken my family to the Gaylord in December to see the decorations, the reindeer, the Ice exhibit and other great things to do there. My only issue was that during that time (late Nov-Dec) you have all the local Dallas people coming to take pictures there but not staying at the hotel. This cause a traffic and parking nightmare. My recommendation would be to have an offsite or other location for people visiting the hotel and the normal parking garages for the hotel guests. It would make for a much more pleasant experience.