This past December and a couple of others I made it a point to take part of a day - well the best part of a day and rode buses, monorails and boats without going to a park. I went to the monorail resorts, the boardwalk resorts and Widlerness Lodge and Downtown Disney just to look at the Christmas decorations. One year my son and I did the Segway tour at Epcot which was fun. I know you said this is a trip without kids - my son was in his twenties at the time. it might also be a time to do a tour that is limited to adults like the backstage magic one. We also did Blizzrd Beach one year and it was really empty that day. We had a ball and got a laugh about the lifeguard in their long pants and jackets. It was really not that cold but they seemed to think so. It is a get time to go to Disney - be prepared for any kind of weather and depending on when in December you are going for any size crowds. Have a magical trip.