My son and I tackled one of the "Demanding" hikes at Mount Diablo. Apart from a few sore muscles and joints, we had a great time.

From from the summit, or near the summit, back to where we started. Way down by the quarry in the middle left.
The two of us at the summit tower.
View of the back side from the summit.
Me looking down at the back side.
Nick looking down at the back side.
View of the summit from the back side.
Heart rate graph of the climb.