Past Community Rides with Bike Sunnyvale (6-11 mi)
There are two recreational bike clubs that cover the area - Western Wheelers which tends to have rides from Sunnyvale up the peninsula and ACTC which tends to have rides from Sunnyvale southward. Check out their websites: https://westernwheelersbicycleclub.wildapricot.org and https://www.actc.org/. If you're not looking for group rides, they still have routes that you might like and that you could do sections of if you don't want as many miles. The Western Wheelers Long Distance Training (LDT) series starts in Jan if you're looking to build up to longer and longer rides. There are multiple routes/groups so you can pick the one that is best for your level.