From Watendlath take the path to the east of Watendlath Tarn and continue south. In good weather, the Wainwright guide is sufficient for navigation. After the path has turned into a rock staircase, look for a branch to the right and find your way to the 'top' of the Crag. Oddly, the summit of Great Crag listed in the Wainwright Guide is NOT the highest point - a second summit to the south is slightly higher.
After ascending the Crag, return to the path and continue South to visit Dock Tarn - an idyllic beauty spot that should not be missed, especially on a fine summer's day.