George Maharis has died at the very advanced age of 94. From the NYTimes, where that publicity photo came from, I learned that Maharis was gay. (Bring back white sidewall tires!)
https://www.nytimes.com/2023/05/28/arts/television/george-maharis-dead.html
Curiously, there’s no direct mention of his orientation in the Hollywood Reporter obituary, despite it having been relevant to his leaving the series.
https://www.hollywoodreporter.com/tv/tv-news/george-maharis-dead-route-66-star-1235502542/
Maharis’ character was obviously based upon Jack Kerouac, with co-star Martin Milner looking like Brian Wilson’s older brother who wasn’t in the Beach Boys. The pilot episode of Route 66 is excellent, with strong adult content. The memorable theme was by Nelson Riddle, who wrote the equally memorable theme to the Batman TV series.
CORRECTION: A certain gentleman going by the name of “Denro” says, “Riddle me this, Nelson. The Batman theme was written by Neal Hefti!” Here are some Batunes that Riddle did compose, borrowing liberally from Hefti’s ditty: