The fictional camp for discarded wives - Finedale, is supposedly in the Napa Valley. The camp does not exist even though many readers have suggested it be built since it could go to good use in real life!
The location I visualized when describing Finedale was in the southern end of the valley called the Carneros Region. It is where they primarily grow Chardonnay grapes. The photo below is from on top of the hill where I described a field of lavender - that's where Grace sits with Lucille and talks about relationships. Within that chapter there are several clues dropped that the reader hopefully picked up on about Lucille.