Access the trail from the top of Crooked Run road (State Road #720) and the intersection of the Laurel Run Trail
As soon as you begin heading south on the Great North Mountain Trail (1009) you'll encounter a fair bit of rocks and a steep climb. If you are alarmed by the rockiness of the trail, rest assured that this is the rockiest section of trail on the entire ridge. After a short but challenging climb, the trail drops very steeply, quickly and rockily. Right as the trail begins to drop there are phenomenal views off to the east side of the trail (left side if you are headed south). Make sure you stop and enjoy the view from the rocky outcroppings.
After some steep up and downs (again all the steepest sections of the ridge are on this northern end) you'll come to a trail intersection. This is where most folks miss the trail. You'll pass a very clearly marked intersection for the Stack Rock Trail (Trail #568B), blazed purple. Very shortly afterwards it will appear that the trail continues straight when in fact it takes a sharp right turn to remain on orange blazed ridge trail. If you continue straight you'll start to descend quickly (dropping off the ridge) on the Falls Ridge Trail (Trail #572), blaze yellow. REMEMBER TO STAY ON THE RIDGE TRAIL.
After this intersection you'll continue on the North Mountain Trail (1009) until you reach the communication towers at the top of Crooked Run rd.