I understand that 1 and 101 are the same in the southern part of the route. I did see a reference to Hearst Castle being a 2 hour detour which is simply not true if they are coming down 1. You drive right by. Now the tour, of course, involves a couple of hours but I would hardly consider that a "detour."

Perhaps I was reading too much into one comment.

I am just strongly suggesting the OP stay on 1 all the way from San Fran until it joins up with 101 at San Luis Obispo. That would give the maximum scenic value and take him through the real Central Coast via Monterey, Carmel, Big Sur, San Simeon, Cambria, Cayucos and Morro Bay. An overnight at one of these in place of a cancelled night in Napa would pay huge dividends. The inland route via Salinas, King City, Paso Robles and Atascadero just sucks unless you simply must make the best time.