Coming through Atlanta on a Friday, before 2pm all of the expressways are pretty good.
The closer to 3pm you get, the more likely you'll hit traffic on the Southside, leaving Atlanta.
If you do make it to the northern outskirts before 3pm, your best bet is to follow 85 (from the northeast side) or 75 (northwest) straight through the center of Atlanta, making sure to remain on 75 south to reach AMS.
If you have two people in the vehicle, you qualify for the HOV lane (far left) through the city on 75 and 85. While it may not be faster than the other lanes, it has far fewer stunt drivers jumping across 6 lanes to get one car ahead of everyone else. In the HOV lane you can maintain a reasonable tow speed, and you don't have the right lane constantly becoming an "Exit Only" lane on you. If you can't run in the HOV lane at a reasonable pace, don't exceed 85mph in the open lanes even if everyone else is doing it. You have an out of state plate, and the speed limit is as low as 45mph in places.
Use the 285 bypass after 3pm, being careful to not miss 75 South.
If you are towing, be aware that traffic will go from an 80 mph cruising speed to zero almost immediately when the stunt drivers start causing problems.