Highway 1 is the one you want. The 101 is inland of the coastal mountains and has a pretty bleh view for the most part. Wine country is north of San Francisco, and you can make a day trip out of it. I'd suggest getting one of those Gray Line bus tours of wine country if your MIL is setting the agenda for the day, plus you'll be able to consume at the tasting rooms of the vineyards without worry. I survived the experience without being too terribly bored as a 13-year old, so your kids will probably be able to tolerate it as well.