To get from Feynan to  Petra, one has two options. The first is a relatively normal road, with pavement and double lanes. This is the longer road. The second one, which I took when driving to Petra, Shobak, and several places in between, is called Namila. By any light, the long, snaky road with dozens of hairpin turns is beautiful, albeit in a slightly Mordorian way. The geological diversity is nowhere near as extreme as it is within the Dana Biosphere Reserve, but impressive nonetheless. Panorama below (click image for higher resolution):