We did a US west coast road trip in 2019 (our last holiday before covid/lockdowns).
Washington
3 nights Seattle - Space Needle, Pike Place, original Starbucks, gum wall, Amazon hq
Oregon
3 nights Portland - Voodoo Donuts, powells bookstore, twilight filming locations, multnomah falls, hood river, mount hood, trillium lake
2 nights Oregon coast - Devils Churn, Thors Well, Heceta Head Lighthouse
California
1 night Jedediah Smith Redwoods state park for giant redwood trees, chandelier tree
2 nights Napa - vineyard tours
3 nights San Francisco - union square, fisherman’s wharf, golden date bridge, Alcatraz, Chinatown, painted ladies, Castro, haight ashbury, coit tower, Lombard street
Drove through Santa Cruz - boardwalk
2 nights Monterey - cannery row, aquarium, 17mile drive, pebble beach
Drove down the coast via big sir all the way to San Luis Obispo - 1night
Drove to solvang for a short visit & carried on to LA
2 nights Anaheim - Disney
2 nights West Hollywood - Griffith observatory, downtown LA, Hollywood sign, shopping, nightlife
You could probably spend 2 full weeks just between San Francisco & Los Angeles. Plenty to see & do to fill all of your days. Los Angeles is fab for teens. They might enjoy Universal Studios & Warner Bros tours aswell as Disney. Walk of Fame is fun & you can check online for movies being filmed, so might see some celebs. Could take in a American football game at the Staples Center depending on their schedule.
I have been to LA, SF & San Diego a few times. You will absolutely love it. And road trips are my favourite kind of holiday.
I would probably agree that you leave NYC for another trip.
and finished in Los Angeles. We visited Portland, Oregon coast (I particularly liked the southern Oregon coast),