It won't be much help for the OP or his wife, at least for the moment, but I thought I'd mention that the Fremont Freewheelers club has a series of training rides leading up to the women-only Cinderella ride.
The Mission of the Fremont Freewheelers Cinderella Training rides is: "To teach women to safely ride a bicycle in a group setting and to help them develop the skills needed to successfully complete the Valley Spokesmen Cinderella Classic." The Cinderella Classic is a 100 kilometer women-only bicycle ride sponsored by the Valley Spokesmen Bicycle Club. That series already started in January, but might be something to keep in mind for next year. Other clubs closer to Pleasant Hill / Martinez might have similar ride series.
This was my own introduction to road cycling, many moons ago.