Visiting Dehang on the way from Zhangjiajie to Fenghuang

We are hiring a car & driver to take us to Fenghuang from Zhangjiajie early morning in September. I heard about the scenic spot TIANWEN Platform in Dehang and wondered if I have enough time to stop for a visit. Is it hard to get to or easy to get to? Where is the path? How long does it take to walk there and back? How close can we get to it or how many miles away from town center is it?