You might like to consider reversing your trip.
Hi Roger, and Welcome to the Great American Roadtrip Forum.
First thing that jumped out at me with your plan is to reverse the trip. The Pacific Coast Highway between San Francisco and Los Angeles is best driven from north to south. That way you have the ocean on your side, avoiding the need to cross over oncoming traffic each time you turn into and out of the many view points and scenic overlooks.
Do you have any maps of the US from your past employment? They would be extremely helpful in planning a trip like this. Good maps would show you all the other things there are along the way for you to consider including in your loop. Sites such as the many other national parks in the region, scenic routes as well as historical and touristy attractions.
If you do not have maps, or do not have access to maps locally, may I suggest a Rand McNally road atlas, which can be purchased from the RTA store at the bottom of this page. Order it now and you'll have it in a couple of weeks.
Good maps are invaluable during the planning, and essential when on the road.
Enjoy the planning.
Lifey