I totally get the appeal of driving PCH from one end to the other. As someone who has done it in part or whole a few times in the last 10 years between LA and parts just north of SF, it can be a taxing, frustrating drive choked with traffic. You get behind some slow trucks or vehicles, and it really can spoil the experience. The immediate area north of Jenner (contains some of the more hair-raising bits which are not at all fun if anyone in your car has any vertigo or fear of heights. Still, as much as I try to downplay the experience, I get it. I personally think that central coast area is amazing - Santa Barbara is what every really wants when the think of golden CA beaches and wine country (Buelton, Los Olivos), and the PCH area around Cambria is really nice. If you start from SoCal, I'd not bother with PCH and just figure out how to get to Cambria the most efficient way possible and start your journey there.
I've not driven it north of Mendocino, but am told that arguably the section from mid-Oregon to Eureka is very scenic (perhaps the nicest stretch of it all), and I wonder if you might get the best experience by focusing the driving bit to a smaller section with some overnight stays in small beach towns?