......but we are talking about a summer *weekend* in August people.
Prime beach season....with the crowds that go with that.

PCH (Highway 1) is apt to be a parking lot from Santa Monica to Trancas, with stop-and-go traffic as beach-goers clog the road. Only if you plan to get a very early start, (before 8 am) would I consider this route...

I personally would take Interstate 405 North to Interstate 101 West. You will still get some lovely ocean views from Ventura North to Santa Barbara. And if shopping is your thing, Camarillo Outlet Mall is along the 101. And I'd agree that Santa Barbara is a lovely town to explore. Planning more time there is hard to fault.

For a trip out of town, if you're not a wine snob, you might consider a trip out to Lompoc to visit La Purisima Mission State Historic Park, an old mission & rancho from the Spanish settlement period of California....or a beach trip & picnic at Jalama on the "lost coast" between Pt. Arguello and Pt. Conception.