This is great you are writing about your bicycle travels!
I wanted to clear a few things up and point you to some resources on our website that might help.
You mention the "Bike Travel Association." I've never heard of this organization.
As far as I know, there was and is no Bike Travel Association. It was a tagline used by Bikecentennial in the early years of the organization.
You list the distance of the TransAm as 4275. I guess it might have been that when you rode, but the ACA currently lists the distance as 4228.
Indeed. While the TransAmerica Trail is still mostly the same as it was in 1976, there have been modifications made along the way. The result would be changes in total mileage for the route.
If you want to clarify your organizational history we have a detailed article available:https://www.adventurecycling.org/about-us/history/
Also a timeline of when different things have occurred over the years:https://www.adventurecycling.org/about-us/history/adventure-cycling-timeline/
And to reminisce about the story in one place along with some great photos, see our 40th Anniversary book about the Trail:https://www.adventurecycling.org/cyclosource-store/40th-anniversary/sp/adventure-cycling-association-transam-book/
I hope this is helpful!