Oh we went last summer, and yes, it was the best family holiday with teens ever. My kids were the perfect age, 16 and 18. I'll give you our itinerary. I wouldn't change a thing. Disclaimer, we weren't bothered about theme parks at all and are not into all the Hollywood stuff either so we just drove through LA and didn't visit it at all. Might go for a few days on a future trip. We'd want to see the Griffith observatory and walk up to the Hollywood sign and probably not much else.
Started with 3 nights in San Francisco staying in Fisherman's Wharf (got there in the evening.) Went to Alcatraz next morning then mooched round FW area, walking to North Beach for a pizza for dinner. Had a guided bus tour next day which showed us all the sights and then took us over the Golden Gate Bridge to see the redwoods at Muir Woods and then onto Sausalito for lunch (gorgeous little place). More of the sights of the city in the afternoon then we got on a tram and Metro to the Castro area and ate like a local in a Mexican place (very rough and ready but delicious cheap food).
I loved San Francisco. Yes, there are dodgy areas and it's sad to see the homeless but do your research and you will have a great time. Some people hate it but I come from a city anyway which can be a little edgy in parts so I'm not exactly sheltered. We still haven't seen everything we want to see so will go back again at some point.
Picked up our hire car next day and went to a fab hotel just outside the western entrance to Yosemite for 4 nights. That was a real treat, it was so nice and of course Yosemite was absolutely amazing, out of this world. We like walking so really enjoyed it, and saw the high country of Yosemite too (Alpine lakes, different terrain etc).
Drove back to the coast for 2 nights in Monterey. Went to the fab aquarium at Cannery Row (good if you've read any John Steinbeck) and also whale watching (bit disappointing, we did see one whale but just a glimpse really, I think we were just unlucky as apparently most people get a good view of them). We did see dolphins, sea otters, sea lions and a sun fish though. We visited Carmel while we were there and drove round 17-Mile Drive and had a lovely walk. I love the coastline round there. Eldest wasn't keen on Carmel, he thought it was full of rich old white people 
and not diverse enough, far too sanitised!
Then onto the Pacific Coast Highway down through Big Sur. An amazing drive, loved it, loads of things to see on the way. Stopped for 2 nights at a quiet little place called Cambria where we visited Hearst Castle (really interesting, nothing like our English castles!) and saw a beach full of elephant seals, like something off a David Attenborough documentary! Again we enjoyed a walk along the boardwalk at the beach and had a wander round the little town. We stayed at a cutesie place which reminded me of the Dirty Dancing hotel!
Onto Santa Barbara for 2 nights via lunch in Solvang, a Danish settlement, which has very Danish style architecture and bakeries etc. We had a beach motel in Santa Barbara, near Stearns Wharf. Loved Santa Barbara, all the Spanish style architecture. It has a great cycle path which goes all along the beach so we used the hotel's bikes (really easy and seemed to go so fast) and cycled to Montecito and mooched about on the beach where probably Harry and Meghan have probably been a few times. It was absolutely gorgeous. Had pizza in the Funk Zone, and then another night we had dinner in a fish restaurant in the harbour.
We then had 2 nights in Laguna Beach for a proper rest. Spent the day at the beach, caught up on washing etc , enjoyed the restaurants and atmosphere in the evenings.
Our final stop was San Diego for 5 nights staying on a high floor in a modern hotel in the harbour with just fantastic views. Pool, rooftop cinema club etc etc. Now THAT is an amazing city. So modern and clean (although it does have its homeless too, due to the mild climate I think). There is so much to see and do and the climate is perfect. We spent hours on the USS Midway. Whoever would have thought that a naval aircraft carrier would have been so interesting!! THere is loads of military stuff going on around there, I think the navy seals do training exercises because we saw lots going on, was great to watch from our hotel window. The Top Gun bar was just over the road (where Tom Cruise sang to Kelly whatserface) however my boys and husband refused to go in - still annoyed at them! We got the ferry to Coronado Island where they filmed Some Like it Hot and had lunch at the Hotel Del Coronado. Went to Balboa Park where we spent all day one day at the zoo. Then the next day we went back for the museums and to walk around. We loved all the Mexican stuff, plenty of tacos were eaten in San Diego! oh and we went to a proper American barbecue in an outside restaurant, so delicious! We would go back again as even though we went for 5 nights there was still stuff we'd like to see, and of course you can't ever have too many tacos!!
I'm not going to lie, it was an expensive trip, a one off the way we did it. The cost of things, particularly food, was outrageous. It's not a cheap part of the world anymore. But we got the California bug and want to go back to see some of the gold rush towns, and to see Lake Tahoe and Mammoth Lakes. And some of the deserts in a cooler part of the year. The flights are cheapest when they first come out in the autumn. We booked in January because COVID travel was a concern at the time.
Hope I haven't bored you! If you want to get REALLY obsessed, join a FB group called California Dreamers and West Coast Wanderers. It was recommended to me by someone on here and was totally invaluable in our planning. Really really helpful. And this time of year you get to see everyone's photos and blogs etc, really gives you a taste for what you want to see.