As has already been said, rides from home are easier. Nice thing about short tours from San Francisco is that you'll almost certainly be within convenient reach of services, should you have forgotten some essential. From San Francisco, southbound 1 is nice, but the return trip is often into a pretty stout headwind if you don't set out early. A short-ish run to the hostel at Pigeon Point light puts you near Pescadero for food options. Then a run down to Santa Cruz or the hiker-biker campground at New Brighton in Capitola before returning would be a nice introduction. Not too hilly, challenging enough, and not particularly remote. The stunning scenery is a bonus.