Yippee, we made it to Napa!! Although she was sure that she hid it well, the day mum was dreading arrived. Driving? In SF? Us? There had been subtle hints about tours that looked good, other ways of getting around, but like a good mum, she didn't stop me from striving for my dreams....!
(Maybe pick-up wasn't the right time to tell her my brilliant idea - that, to me, it made perfect sense to keep the car overnight and drive to the airport the next morning. I think at that point she did actually go white!).
We had such a lovely day. It was raining, so we didn't really "see" the Napa or Sonoma valley, but we did get to see amazing cellar doors, wine caves, taste a little bit of wine and see the beginnings of autumn.
I think even mum was glad we went...!

PS. Drove the car to the airport this morning and proudly handed it back, intact, undamaged and without any scares for mother. All in all, a success!