Melanie and Ruth, especially, thanks for your advice. I just spent four lovely days in Sonoma/Napa that started with a trip to the In-N-Out Burger-Krispy Kreme megaplex in Daly City and climaxed at a barrel tasting for O'Shaugnessy Winery's 2000 Cabernet to be released next year.
Based on recs from this board, we dined at Zazu and had a very good meal. My highlights were an arugula salad with house cured duck prosciutto and grilled dourade with shaved fennel and local olives. Simple preparations that focussed on the produce. (By the way, based on the address and some old signage, it appears that the Willowood Market cafe space is now Zazu.)
I also tried the Santa Rosa taco trucks, concentrating on Elenita at the Bad Benita gas station. They had no pambazos, unfortunately. I sampled lengua and cabeza tacos, a fajita, and a milanesa torta. All were very good. The tiny tacos were especially flavorful as the slow cooked meats lend themselves to long days simmering in the truck. Though not hand made, the tortillas were excellent. The torta stood out because of the bread. In Chicago, most torta stands use a much larger, drier, bolillo with some of the inside removed. The truck instead used an extremely delicate, moist roll -- like brioche. Not that one kind of bread stands out as best, but it was nice to see something different. In terms of variety and overall experience, it would be unfair to compare the Santa Rosa trucks to the wild bazaar that Maxwell St. market is. (Not to mention the presence of many vendors from the southernmost Mexican states.) But what a great Chowhound call the trucks are-- the food at at the Elenita truck was super, and I doubt the hotel concierge would have mentioned it. Thanks again for the help.
I also want to mention the Fiesta super market in Sebastapol. What a great place. More and better selections of meats (cured and fresh), cheeses, vegs, etc. than I have seen most anywhere. And not just local stuff: the selection of Spanish suasages and cheeses was amazing.
And to top off my trip, fresh, ripe figs of all varieties were everywhere. I love to find something that is expensive and hard to come by back home but cheap and plentiful at my destination. Figs were it this time.