Flight
Georgia has a few different airports, but Hartsfield is the easiest to get to and from. Delta has direct flights to and from Rochester, and most other airports. It also has its own terminal making it a little easier to get to on your way back- food for thought if you're picking between one or the other!
Train
We take the MARTA when we travel in and out of Atlanta to the airport. There is a station within the airport for you to get on, and it only goes on direction from the airport so can't go wrong! You are trying to get to North GA, so take the MARTA for a couple bucks to the very last stop. You can catch an uber or a ride from an in town guest from there. Depending on time of day you land, ATL traffic can be pretty tragic. So this can save you some time and money!