Our hike was the North Chickamauga Creek Gorge from the park trailhead to the campsite at the confluence of Cooper and the North Chickamauga Creeks; and then we returned.
We lunched before our return hike to the trailhead. The return starts with the most rigorous part of the trail ( about a 1 mile climb to more level parts of the trail).
Overall I'd rate the hike as moderately strenuous with about half the hike being rated strenuous. The actual hiking time was a little under 5 hours.
Views along the trail are beautiful; and a significant part of the hike is along the creek bluffs that allow one to look into the deep gorges. The creeks that flow into the canyon are still flowing well.