You will have no problems driving through town on a Sat morning. They just finished a big construction project so there are now like 8 lanes in each direction through downtown.
My one piece of advice for Atlanta traffic... HOV LANE!!!
And if you need a good place to stay, there are a lot of great choices at the Barrett Pkwy exit off I-75 in Kennesaw. Major mall area, lots of places to eat, sleep, and shop!
Have a safe trip!