Mine was 1975 from E Lansing MI to Toronto. It was with my girlfriend who became my wife not long after. We did have a customs search when returning to the States.
For the next 20 years we did not bike tour much. We did some backpacking trips. Since 1995, we have enjoyed a bike tour each year. Some backpacking events as well, Fortunately still healthy enough to continue the streak. Heading back to Canada on a self contained credit card tour later this summer.