Welcome Linda. Sacramento has a large and diverse cycling community. I would look into the Sacramento Wheelmen. The core members of the group are mature guys/gals and if you can do 44 miles on the ARBT you can do most of the rides no problem. They have a lot of weekday rides that utilize the ARBT too.
www.sacwheelmen.org
Another club that is a little more low-key is the bike hikers. Don't know their web address though...
See you around.
-Chris