Your best best is probably just joining in on an informal ride when they are announced.
Additionally, there are many many formally organized rides scheduled. I highly recommend the Berkshire Big Bike Adventure Ride (BBA). It's a 2 day event, but you don't have to do both days. The route is basically dirt roads with optional parts that are more challenging for those that like that sort of thing. This will be my 3rd time, so yea, it's a good time.