I just hiked the Russell Peak Loop yesterday for the umpteenth time and felt compelled to draw attention to it again. This is an easily accessible hike that starts near Happy Valley Elementary School in Lafayette and winds up to Russell Peak (1357 feet) in Briones Regional Park. The views from the top are incredible! You can see the north Bay, Mt. Tamalpais, Briones Reservoir, Round Top at Sibley, Rocky Ridge, Mt. Diablo, and more. This is a great hike to do from Feb-May while the hills are green. I just added a few more details to the original post.
The Undiscovered Hikes of Lamorinda 
One somewhat important detail that is omitted from this description is that the road up to the trail head ends at a private road and there is no parking nearby. You have to hike up a private drive to get to the trail. I have no idea how the property owner feels about this but there is a no trespassing sign posted.
Hi Jim, you need to click on the link to “original post” to see all the details about the hike. Parking is on the bottom part of Panorama Drive before the “END” sign. Hiking up the private road to get to the trail is fine.