There is some street parking right in front of their location.
You can park on the street pretty much right in front of their location. Just google their address. Anywhere on the street around it is fine. Have fun!
We took our tour on the weekend and there was ample parking on the surrounding streets. On weekdays, I suspect that you might have to use paid parking. Ask the Touring company for the nearest parking if the side streets are filled. Atlanta has a parking app called “ParkMobile”. I highly recommend that you download it!