Fall color in the Cohuttas usually peaks in mid to late October, a week or two behind the high-elevation show in the Smokies to the north and a week or two ahead of the valleys around Atlanta. Elevation drives most of it. The ridge tops turn first, the coves and creek bottoms last, and driving up in elevation on a given day can put you in two different seasons an hour apart.
The easiest way to see it costs nothing but a tank of gas. The forest road climbing Potato Patch Mountain, on the Holly Creek side, runs through hardwood the whole way up, and the view does not need a trailhead or a pack. Up at Lake Conasauga, the highest lake in Georgia, the color and the elevation together do something unusual: it feels less like north Georgia and more like a lake somewhere much farther north. That drive alone, on the right week, is worth the trip.
For a trail, the recommendation here is the Jacks River Trail. Water runs lower in fall, which means easier, shallower crossings on a trail known for its twenty-plus fords. The bigger reason is the mix. Low-elevation hardwood and high-elevation species meet along this corridor in a way that does not happen on most single trails in the range, and the effect in October is a real gradient of color, not just one species turning at one time. Hemlock holds its green through all of it, and against a hillside going orange and yellow, that green reads as sharply as anything in the Southern Appalachians.
Come on a weekday if you can. The Fire Tower and Lake Conasauga see the heaviest fall traffic in the range, and the small lots fill by mid-morning on October weekends.