just looking through the most recent edition of Wine Country This Week and came across an ad for an app called “Wine Geek”. pretty comprehensive listing of open-to-the-public wineries and tasting rooms from across CA. searches can be broken down by region, varietal, and deals. map feature works very well. could be a useful tool when visiting new regions without a schedule in place beforehand.
[note: i’m not affiliated with the publication or the app in any way]