The Mountain Winery shows will be the more conservative of the Bay Area shows. This venue appeals to the Silicon Valley crowd, so it will be a mixed bag of people; some there to see Stevie specifically and many casual/non-fans looking for a fun night out. I wouldn't be surprised if there were a bunch of Silicon Valley CEOs in the front row, maybe even Larry Ellison! There are a lot of expensive restaurants and places for wine tasting on site, so it's a different kind of concert experience, very mellow, but high-end.
It's hard to get up to this venue (literally driving up the mountains), so allow PLENTY of time for traffic. I'd suggest at least 90 minutes because I recall it being a single road for at least part of the way. Be sure to park by the entrance as it is EXTREMELY difficult to get out of the venue after the concert (this was not thought out very well). One way in, one way out. When I saw Margaret Cho there last year, it took almost an hour to exit the venue, much of time spent in the car not moving. I don't think there is any other easy way to get to this venue (e.g. public transit).
The Fillmore shows, on the other hand, will be the true rock and roll experience

Given it's small size, it will be packed with just diehards. It's basically general admission, standing room only with very limited side seating on the first and and second levels.
I'm debating whether I'll go to the Mountain Winery show. But I'm definitely doing the Fillmore.