The weekend after New Year's might be the marathon weekend. I "ran" in it last year and it was right around that time. Certain hotels will be very crowded with charity organizations. Last year, I believe they were PO (where our group stayed) and CB. I'm not sure about this year. Might want to look into it. In any case, the crowds weren't bad, but the weather is a bit unpredictable. One year I was wearing sweatshirts and long pants. Last year it was HOT - shorts, and t-shirts.