>>1837774I would suggest Gregory's Bald in Cades Cove and Brushy Mountain/Porter's Creek in Greenbrier for marked trail day hikes. They're beautiful and typically don't see a lot of foot traffic. As for unmarked trails, there's a trail colloquially known as Rhododendron Creek where you'll find roughly ten waterfalls. Here's a picture of my wife and I at Rhododendron Creek.