I did this time frame the past two years. In fact, I'm pretty sure I went Jan 3-11 two years ago...
This is what should happen: Jan 2, the day before you get there, everyone should be leaving to get back to school. January 3rd and 4th will be dead. Thursday the 5th you will notice more people checking in, but still slow. Lots of people will arrive Friday 6th for marathon weekend, but still not bad.
It will be hard to get around marathon weekend (7th and 8th) in the mornings, as people are getting to their races. Plan to be in a convenient park those days. Not too bad, otherwise. On Sunday/Monday, marathoners will be leaving. Tuesday and Wednesday, 10 and 11, will be slow, once again. Crowds will start arriving for MLK weekend later in the week, but you will be gone by then.
These are my predictions! Also, I did not see tour groups! Bonus dollars!
You are going during a good time, I really don't think it gets much slower than this.