The first part of this wildly popular hiking trail is good for running too, with mostly solid dirt tread and enough rocks or streams across to make it feel interesting, but not turn into a full-on steeplechase. Soon after the trail starts up a steep ridge, though, it enters a massive, jungle-gym-like field of boulders that would thwart even the most seasoned of runners. (You could drop out of a run and hike your way through the boulders to continue past this point, if you so desire.)