Hi,
I'll be there over New Years too. It is wonderful because everyone is out, walking around town and celebrating together. Defintely get a room now. When I worked on Ambergris most places were booked solid that time of year. It is more crowded, but it's kind of nice. The good part is that there are so many people, most trips go, versus in the slow season, sometimes trips are cancelled because of not reaching minimum numbers.