When we arrived at the trail, the parking attendant told us that the graham hill trail was actually 1.1 miles and overrun with poison oak (ok for people but not so much for dogs).

She recommended going down a mile south towards treetop drive to pipeline trail, which was a in and out trail that totaled 6.6 miles. That was beautiful, on a paved path, featured amazing redwoods, some views, and a river. Also free parking!