I have driven CA Hwy 1/US 101 from Canada to Mexico and have to agree with the comments made in praise of it. And shorter trips many time. Unlike most East Coast beaches you are elevated enuf to really see the rocky cliffs and narrow beaches.
However with just a few days you need a plan. After awhile the beach towns just sort of run together, but with gorgeous coastal views in between.
If my old home SD is the prime destination, I'd say you'd want to roam no farther south than Tijuana and not north of Newport Beach.
Weather will suck in Feb, take raincoats and sweaters. Also check routes for for mudslides with current rain conditions. PCH near Malibu used to wash out regularly.
I do not like TJ, but a lot of people want to say they've been there. Like my wife and I took her in Feb

.
SD Zoo is killer. In Balboa Park near historic Old Town. If you go early and don't dawdle you can take in the zoo in a morning, lunch in Old Town and head to La Jolla Cove for happy hour.
The Wild Animal Park in North County is great. Sea World and Mission Bay might float your boat also.
The weekend brunch at Hotel Del Coronado is spectacular, and you can walk the grounds to recover.
Then more PCH to Mission San Juan Capistrano and then Laguna Beach, an artists hangout and nice beachfront town. Probably make Corona Del Mar in Newport depending how much you stop for.
Vasek Polak Porsche in Hermosa Beach used to have some interesting cars if you get near there.
And the Petersen Museum in LA has a bunch.
If it is cruising you want it is there in spades. I used to say I hoped to cruise the PCH for my eternity.
Have great trip!