Start at the end of the culvert, 100' downhill from the end of the small parking pullout which is 100 yards down from the main Windy Point parking. Look for a small asphalt water drain - there will be a cairned trail leading down from there towards trees. Hug the base of a rock through the trees, then cross right under the large scree slope above. Head down steeply and come to a small landing.
From the landing, head sharply left, find a huge old tree to cross over, and continue down a steep path which eventually curves right along the base of Rupley Towers. You'll have to tunnel through manzanita at some points.
This trail ends at Bop Til You Drop in a nice big open area.