Sierra Road is tough. It's been a key climb in the Tour of California 2006-2008, of reduced importance in 2009-2010 but still on the route. But the Low-Key Hillclimbs first did Sierra in 1995, and it's additionally one of the climbs in the Devil Mountain Double.
Nothing subtle here: Sierra starts steep and stays that way. It soon enough clears San Jose's sprawl, becoming a scenic rural mountain road with excellent views of the valley.
But bring your low gears for this one: it's tough.
For a nice loop, continue to Felter then descend to Calaveras, eventually returning to Sierra via Piedmont.