The parade happened in 1964 in Soquel, CA. That day’s Santa Cruz Sentinel on page 7 says 60 cartoonists were to be in it, and most of them the day before were in a tournament at the Pasatiempo golf course. George Crenshaw of “Nubbin” and Mrs. Bob Barnes of “The Better Half” we’re the winners (the article does not name anyone else).
Michael J. Fox might have threatened to sue; IIRC it’s just “Mr. Michael” in the anthology reprint.