Yosemite to Monterey only takes about 4 hours,
3 nights in Monterey? Or - for a unique experience - stay a night or two at www.norcalhostels.org/pigeon ? Visit Carmel and Santa Cruz?
Next, book an afternoon tour at Hearst Castle (book early - up to 56 days in advance), and - depending on your interest level - another tour for the next morning (see the choices at hearstcastle.org), you can get there from Monterey in about three hours via Paso Robles and Cambria (highways 68 and 101 and 46 and 1).
Stay two nights in San Simeon or Cambria?
Whatever you wish to see or do in SLO, and which of the many nice places and roads you wish to take after that while heading south will dictate how long it will take you to get to Santa Barbara. Read up on the region.
I suggest approaching Santa Barbara by heading east at Buellton (whether you go there via Lompoc and past the Vandenberg AFB or simply down 101), on highway 246, stop and look around in cutesy-Danish Solvang (famous for yummy bakery items), visit some Santa Ynez winery, or the Reagan library, then take 154 up and over some very picturesque landscapes until you get the big payoff - the vistas over Santa Barbara and the ocean from the top of San Marcos Pass. That’s breathtaking!
Now descend into Santa Barbara and stay in one of the self-contained cottages of the Harbor House ( http://harborhouseinn.com ). Walk out and turn left at the waterfront and go onto the pier or - better in my experience - turn right at the waterfront and walk around the bend into the harbor to the fish restaurants, put your name down, and spend the waiting time by walking out on the concrete spit until you get sprayed on a windy day.
How many nights? Hard to say, read up on everything available to see and do in the region and decide for yourselves.
As you head towards Los Angeles, get off the 101 in Oxnard just past Ventura, take exit 62B and Oxnard Blvd going southeast becomes Pacific Coast Highway PCH. Not long past Point Mugu Rock (by now you’re right by the water), on your left, is Neptune’s Net, an iconic fish restaurant, great for the food, the views, and for people watching. Anything from bikers to beach bums to movie stars to lawyers in snazzy cars playing hooky with their mistresses, all sharing well-worn wooden benches and tables. SoCal at its best, and living up to the expectations that nearby Malibu raises...
Watch for speed signs in the l-o-n-g city of Malibu that takes you into Santa Monica and L.A.
Los Angeles has so much to offer to those who choose to ignore the bad rap it gets from people who haven’t taken the trouble to explore it, I can’t begin to suggest how many days you should spend, and where. Anaheim has no soul, just Disney and business conventioneers mostly (I speak from 30 years of experience about the latter...), so make minimal reservations there, or none - you have a car so you can get in and out while staying somewhere nice. Hermosa/Manhattan/Redondo Beach? Santa Monica?
Hope this helps. Enjoy!