The Pacific Coast Highway is arguably the most scenic road in all of America. Don't travel that far and miss it.
Absolutely a must!
There are so many nice places to choose from but a must see and at least a two night stay is in Yosemite but advance reservations (6mo min) are necessary. My preferred route is up HWY395 (past Mt. Whitney, highest peak in North America) to HWY120 west, thru the mountains into Yosemite from the North/West. Haven't done it since the big fire this last August. Then I'd shoot to the coast on HWY 152 to Salinas and do the 17 mile drive thru Monterey and visit Big Sur. Take the Pacific Coast Hwy thru Santa Cruz, Half Moon Bay, San Francisco and the Golden Gate Bridge. There is a redwood state park north of Santa Cruz but the best Giant Redwoods are 200mi north. You're probably pressed for time at this stage and you can jump on I80 and head east. If you have more time, follow the PCH as far north as you can, you will not be disappointed.
Have a safe trip.