Unashamed tram- train tragic, so I'll offer SFO and Northern California recommendations from that biased point of view. I've visited SFO about 20 times since 1978 and it's my favourite city in the US though NY is a close second).
Our favourite hotel is the "Inn at Union Square" on Post Street a couple of doors from Powell Street and Union Square (Saks Fifth Avenue, Macys, Tiffany, Gap, Victoria Secrets etc). The cable car stop is at Post/Powell and you are far more likely to get on a cable car than attempting to join the car down the hill at the Market Street terminus; the wait line there can be 60 minutes. Cable cars leave the terminus with a few spare spots (usually to hang on outside) and there's never a queue to board at Post.
Whilst on the topic of cable cars, be aware that a single ride is $8 - no transfers, no hop-on hop-off. Yet I see (gullible) tourists pay this fare over and over again. You really need to purchase a 1,3 or 7-day Visitor Passport which gives you unlimited travel on all Muni vehicles -bus, trolley bus, trams (streetcars in US parlance), light rail AND CABLE CARS. It's available on your smart device (check out Muni Mobile) or as a paper passport. Fares are $13/$24, $31/$36, $41/$47 for 1/3/7 days on Muni Mobile/Paper.
The Visitor Passport is unlimited which mean you CAN hop-on hop-off where ever you like so you can see it's outstandingly good value for money. We would regularly commute back and forth from Fisherman's Wharf to Union Square or go cable car one way and F-line historic streetcars Embarcadero-Market at Powell the other way. The cable car museum and power house is also worth a visit. You really don't need a car in SFO as all the sites are easily accessed by public transport.
A filling breakfast can be enjoyed at Hollywood Cafe (one block towards Fisherman's Wharf from the Mason-Powell cable car terminus).
Brilliant seafood lunch at the Hog Island Oyster Company inside the Ferry Building - oysters (of course!) shucked right in front of you, clam chowder (of course), and a brilliant, filling sensational "rustic seafood stew" that makes my taste buds tingle and mouth water just typing its name.
Also in the Ferry Building is Blue Bottle - a coffee shop that makes decent coffees (a rarity as the US seems to do their best to destroy one's taste for coffee with that brown sludge they serve up in hotels and restaurants). I complimented the barista on my cafe latte remarking how hard it was to get a decent coffee in SFO: he replied he'd spent two years in Lygon Street learning his craft!
Alcatraz is a must (my kids remarked how realistic Alcatraz was compared to the Tony Hawke Pro Skater game they'd been playing at home on their Playstations and knew their way around the prison perfectly).
Also take a ferry across to the lovely little town of Sausalito. Opposite the carpark and ferry terminal on the main drag and opposite a pedestrian crossing is a small hole-in-the-wall hamburger joint that serves the most juicy, flavoursome hamburgers cooked on a rotating grill in the window. Mrs C found it back in 1984 whilst I was at a conference in SFO and dragged me across the Bay to sample their burgers - she said she'd watched the local police and postman all pull up and order their burgers there so figured they have to be good. We make a point of having a burger there every time we visit SFO (it's much better than that other AFF favourite In-n-Out on Jefferson at Fisherman's Wharf). Order your burgers (usually a queue out the door) and sit in the park to eat them - on your Spotify app play "Sitting on the Dock of the Bay" by Otis Redding (written by him about Sausalito in the late 60s and released after his death in a plane crash) to complete a most memorable visit.
I'm pleased to see you'll drive the Cabrillo Highway from north to south (I think it's a better option than south-north) - it makes diving off the road and parking at every photo location so much easier. The Roaring Camp and Big Trees Railroad near Santa Cruz is a lovely train trip up into the Redwoods if you haven't allowed time in SFO to go to Muir Woods for example.
Monterey, Bixby Bridge and Big Sur - see Monterey report link in my signature (report came to sudden halt as I was unable to upload ant further photos as I had hit my limit - must've been when I was a newbie report writer). What I would have added in the report was a visit to the Monterey Bay aquarium in Cannery Row in Monterey (yes, there's a sculpture of John Steinbeck on Cannery Row which is now a much more upmarket tourist hub than John Steinbeck's depression era setting ever envisaged). I found the "Open Sea" exhibit the most remarkable - a huge 25m high glass walled aquarium with schools of tuna, sharks and a massive sunfish. The jellyfish exhibit, the kelp forest, the seals were all awesome as well. I even got to pat a stingray!
About two hours south of Monterey is Hearst Castle near the township of San Simeon, well worth a visit on your journey to LA. Named after Randolf Hearst the publishing magnate it's an example ofWest Coast over-the-top excess and extravagant wealth that characterised the magnates of the early 20th Century and their need to outdo each other (like the east coast's Vizcaya Museum in Miami or Flagler Museum in Palm Beach).
I'll add more as I think of it.