Just driving to Hearst Castle is close to a 2 hour detour - I would assume that anyone making that drive would actually want to see the inside of the place.

And yes, you couldn't pick a worse time to drive through L.A. than Friday afternoon.

If your wife's pregnancy leads you to skip the Napa/Sonoma winery tours and tastings, might I suggest that you take far less time and just drive through some vineyard areas in the Santa Maria-Santa Ynez area instead - It's at least as scenic as Napa and Sonoma. My recommendation is to get off of the 101 just south of Santa Maria and take Orcutt road to Foxen Canyon Road south toward Los Olivos, IMHO, Foxen Canyon is one of the most scenic wine country drives in California, then continue on the 154 past Lake Cachuma down into Santa Barbara. If you want to stop at a few wineries along this route, Foxen, Zaca Mesa, and Fess Parker are good choices among many. And if you don't actually stop for winetasting, this scenic detour will cost you well under an hour relative to just staying on the 101 all the way to Santa Barbara. Of course, you'll miss Pea Soup Andersen's in Buellton (which is, IMHO, a good thing).