In 1962, Travels with Charley was published. For John Steinbeck, it was the last significant work. He was in a retirement state of mind and this was supposed to be some literary piece describing some trip across the nation. People liked the storyline, the travel agenda, and the characters mentioned.
For me, of the 3000-odd books I've read in my life....I consider it one of the ten best books I ever read.
All this said and done....I've kinda noted over the years various discussions with the book, and how actual events and travels mentioned....didn't really fit well together. Some folks have gone onto discussing the idea that Steinbeck didn't really make the trip, or that he staged two or three of the stops, and just filled in the rest of it with fictional words and descriptions.
A Steinbeck-enthusiast would be shaking their and defend their hero, but then you'd have to imagine this trip, and having discussions with various people along the way.
My humble guess? I think he basically drove the truck out to some Oregon coastal area, and just quietly sat at some cabin writing up the story while gazing at some map and travel books. Six weeks later, he wraps up the piece and mails it off. I don't think it's a terrible thing but it's an odd thing we are stuck with and wondering about.