Wow; what a pessimistic view of Atlanta weather and golf in December! 1 in 3 chance of good golf weather? Couldn't disagree more, or I have a VERY different definition of good weather for golf. I've been in Atlanta for 35 years; year-round golf is one of the BEST things about being here.
Rainfall in Dec. is BELOW average for Atlanta, and the average daily high/low is 54/37. It is rare that there are even frost delays in Atlanta in Dec., and average means that for every day that is 45, there is a day around 60.
As to the turf conditions, the bermuda has gone dormant by Dec., but the soggy conditions are really yet to come for the most part. Dormant bermuda is a great surface until root action completely stops, and often in Dec. there is still a little bit of green showing in the bermuda.
Public courses in the Buckhead area is MUCH more of a problem than the weather, but with a little bit of a drive that is doable as well. Wait until later in the morning when rush hour has died down and the temperature has come up, and go play golf. If you DO decide to come and know more about where you will be staying, PM me and I'll suggest some courses.