Another vote for north to south for the stated reasons.
WRT San Diego. Fear not, San Diegans are humans just like the rest of us and a certain percentage have issues......the others, not so much and you will likely have a great time seeing that part of the coast.
Orange County is a bit sparse for camping spots. Crystal Cove State Park, Doheney, and San Onofre-Christianitos are the ones. I don't believe Huntington Beach State Beach allows tent camping but it is worth checking. I would try to get through Laguna Beach early in the morning as the traffic and lane width conspire to make it unpleasant for cyclists later in the day-that would mean staying at Crystal Cove, which is a fantastic location.
Getting out of Orange County and into San Diego County requires either crossing Marine Corp Base Camp Pendleton or riding on the shoulder of I-5 (if it is passable, there has been construction lately). Camp P requires pre-registration and valid government ID.
Marine Corps Base Camp Pendleton Videos | New Base Access Procedures for Camp Pendleton .
Getting from north of Palos Verdes to the Orange County border is a bit tricky. Do a search on this site, there have been some good posts from Calamaris Chris about the route. In fact his posts are very informative for the southern portion of your route.