Third nomination for Point Reyes.
Remember, if you have a beginner backpacker, even if that person is in excellent shape, a lot of times the equipment issues (comfortable pack, shoes that don't blister) are not quite tweaked yet. I'm conservative with new hikers, usually picking a location that does not require hiking more than 4-6 miles in. If everyone still has energy and good feet after arriving at camp, you can set down your pack and explore further.
In my experience, first-time backpackers also really relish a layover day for dayhiking.
Pt. Reyes is perfect for this. Lots of day-hiking destinations easily reached if you stay in the same camp for 2 nights. Make your reservations online the first hour they become available. I'd recommend Wildcat Camp. (It fills instantly, so be ready.) Sky Camp is another good choice.
Watch the raccoons. They are VERY persistent in going after food.
Agreed that Ohlone is not the very most scenic. I use it more in a training frame of mind ("need to train on some big hills").
– Elizabeth