From the Oakzanita parking lot, head uphill. Soon you come to the first of two stone-hopping creek crossings. Head up the hill and gain a commanding view of the creek. Continue following the creek until you cross again and eventually pop up onto East Mesa Fire Road. At this point, you can continue back or turn right on the road and shortly connect up with Upper Descanso Creek Trail which helps you access Oakzanita Summit Trail which is probably the reason you are here.