The Columbus, Ohio chapter of the A.Y.H. had bike rides as one of their activities since starting in 1939 but they starting ramping up with more rides by 1964 and took over running the Tour of the Scioto River Valley (TOSRV) that had started in 1962. When the bike boom hit in 1971 and ten bazillion bikes were sold to ten bazillion young people looking for a long bike ride, TOSRV was it. I was on the East coast then and whenever cyclists gathered at some point the subject of TOSRV came up. Everyone had to go do it once. At the time there was nothing else like it; three to six thousand cyclists doing a two day 210 mile tour, usually with a little rain.
It was covered by Bicycling! magazine and in Eugene Sloan's Complete Book of Bicycling. The organizers of TOSRV helped other clubs set up large tours in other parts of the country such as TOSRV South, TOSRV West and the NYC Five Borough Ride.
Nowadays there are bigger rides, longer rides, more scenic rides, and tougher rides. We have great choices. Next year is TOSRV 50. I think they should make us all ride Schwinn Varsities just to prove that we are at least as tough as our parents.