Travel at Christmas can be tricky. Usually it is more expensive, and it is likely the place your visiting is celebrating the holiday so folks will want to be with their families. Thus some activities may be limited.
After following your adventures, I think I would look towards Costa Rica. Maybe do a split deal and do lake and mountain hikes around the volcano, and then head to the beach for some relaxation (or vice versa). You can fly into Liberia (LIR) airport and it is about two and half hour drive to the volcano area of Arenal, and only about 40 minutes to the beach. I checked on Kayak and if you avoid the weekends the tickets would run about $850 per ticket.
My wife (really are whole family) is really into Christmas. This may be the first Christmas that as a family we do not gather on the farm together in 40 years. Our grandchildren have reached the age that they need to be in their house on Christmas morning, which we totally understand. We were the same way when they were small. I am not sure if we are going to be in Raleigh or Long Island on Christmas day. I think that is TBD. But if we were to travel over Christmas, I think it would have to be somewhere where the Christmas Magic surrounds us. Cologne, Vienna, or maybe a town in Alsace like Colmar would all be possible candidates for a Christmas getaway.
Wow that sounds good to me - Colmar for Christmas… I wonder if my sweetie would buy off on that one?