Ooga Booga makes a really good point about the possibility of the San Diego Creek Trail being closed due to rain. You will be coming during winter and it's been raining. If weather permits taking the Back Bay trail (Mountains to the Sea Trail & Bikeway on Google Maps) is a really peaceful and protected ride. I personally would drive because If I were you i'd be packing rain gear for the ride just in case and to pack all that for work would be a drag.