Take the Indian Trail Exit (exit 101). Travel east on Indian Trail and cross over Lawrenceville Hwy. (Hwy.29). This then becomes Killian Hill Road. Follow Killian Hill and GGC will be on the right hand side. If you cross over Five Forks Trickum Road, you went too far!
From Stone Mountain Freeway (Hwy.78):
Turn west at Killian Hill Road. Go approximately 3 miles, crossing over Five Forks Trickum, and GGC is the 3rd door on the left.