I can't speak to the specific tour, but I can say that the Chateau St. Jean winery (Sonoma Valley) is a truly beautiful place (the gardens will definitely appeal to your lady) and some of the wines they have available for tasting are only available for purchase at the winery (and they're really quite good).
The only thing I would say about my wine country experience was that it seems like the town where we stayed (at a B&B I cannot recall the name of right now) rolled the sidewalks up at 10pm - it seemed like a rather "dead" place to be for being so geared towards tourists.
I guess that's why going with a tour is probably a better idea, they'll know where to stay, where to eat, and what to do when you're not visiting the wineries.
The sands of time were eroded by the river of constant change.
an empty fermenter is a sad fermenter
Bottled: Nut brown ale, Bink blond clone (she's a bitter Belgian!) Belgian Wit, several other tasty beers that have since been consumed!
On deck: TBD