I was prompted to read this post by the title because I have heard a lot about Bikecentennial, including as a contemporary touring cyclist in 1976. In 1977 my wife and I did a cross country tour from Los Angeles to Washington DC. In Garden City, KS we were approached in the city park by guy in his 20's who had ridden BC the previous year, and GC was his home. He showed us the sights and his family put us up for the night in an apartment above their jewelry store. Such is the fellowship of the Cross-Country Ride.

From the best I can tell, it looks like our routes crossed around Larned, KS. BTW, Bikecentennial has a Wikipedia entry.