Roger...glad to have you join in...as for the group rides, go for it. My wife and I just picked up a tandem over the winter and just started riding in May. The past 3 weekends we did a 50 mile, 30 mile, and a 32 mile group ride. (And this is in the hilly terrain of the Piedmont North Carolina region)

On a group ride you will be able to go at your own pace. There is usually SAG support and adequate rest stops.