Experience the remarkable views of Great Falls, the Potomac River and Too Difficult Run in this popular National Park. We begin at the visitors center heading north along the river, loop around to the south and down to Too Difficult Run following it down to the Potomac. Then up through the hills looping back to the visitors center. Pace 2.5 mph, 600-700 ft. of elevation. 20 minute lunch. Some difficult descents.