Take 321 to Cosby Entrance Road, then stay straight into the campground. Park at the Nature Trail and follow it to the Low Gap Trail. Once on the Low Gap Trail in will be on your first bridge crossing.
At my first bridge crossing along the Low Gap Trail in the Cosby Campground section of the great Smoky Mountains National Park I came across a peculiar rock that caught my attention. I really liked the lines the water was creating as it rolled over the rock, it worked really well composition wise.