The Mountain Bike Trails Project at the Tiger's Lair is a great and growing resource. Follow Ga Hwy 5 west to Whitesburg, about 20 miles. Approximately two miles past Whitesburg, turn left onto McIntosh Drive and follow it 2 miles to the race venue. Follow signs for parking or camping. Equestrians use these trails, too, so remember your etiquette.
Bikes startle horses, and both cyclists and equestrians are at risk.
Most West Georgia mountain bikers know about Windridge ATB Park west of Newnan in Coweta County. On private property, these 8.5 miles of trail are the site of the North Georgia Bicycle Dealers annual Spring and Fall races. If you think you're ready, try the Ironlegs Trail at Choccolocco State Park in Alabama. There are several other trails there, too, with much mellower names like 'Gene's Loop'. Other Alabama trails are found at Cheaha State Park and at Oak Mountain State Park.