There's lots of nice day hikes in the area. Several of the morros have trails or fire roads up them. Montana de Oro State Park has some nice trails, and there are trails all through the coast Range there.
Eastern Sierra? Drive back across the Coast Range, across the Valley, through Bakersfield to Mojave (the town), then north on the 395.
p.s. You'll be closer to the western Sierra, which has one or two nice spots too!