Because he's feeling pretty out of touch with his own country—and he's considered a great American author and all that—John Steinbeck decides to take a road trip around the U.S. to check it out and get a sense of where Americans and their hometowns are at in 1960.
To get all prepped, he commissions a souped-up truck with a little house on the back that he can live in when he isn't crashing at hotels. He calls the truck "Rocinante" after Don Quixote's horse—clever, huh? When he's all set (and after a small run-in with a hurricane just before he was supposed to leave), he and Charley (his French poodle) hit the road.
He starts out by driving over into Connecticut from his home in Long Island (with some assists from ferries, natch) and then heads north into New England. Along the way, he meets a pretty colorful group of characters and learns about their ways of life and their perspectives on the country and its politics. Also, he kind of takes the temperature of regional "temperaments" along the way.
Then he comes back down out of New England and heads west, crossing through New York. He tries to cut through Canada, but he gets into a kerfuffle at the border because Charley doesn't have his proof of rabies vaccination, so he has to turn around. Steinbeck then passes through the Midwest, continuing to offer his reflections and thoughts about the people and places he encounters along the way.
When he gets to Chicago, he puts Charley in a kennel and enjoys a couple of days with his wife, who flew out to meet him. He doesn't give us details of their time together, though.
After that brief interlude, he heads further west into Minnesota and Wisconsin. He hits bad traffic and gets lost around the Twin Cities, and he's charmed by Wisconsin and its dells. He also visits Sauk Centre, the birthplace of author Sinclair Lewis. Then he heads toward Fargo, North Dakota, which apparently had been the subject of his boyhood fantasies. We picture Hawaii when we're fantasizing about faraway places, but okay...
He heads through North Dakota and the Bad Lands, warming up to that area quite a bit when he sees it at sunset (otherwise, it's pretty scary, apparently). When he goes through Montana, he loves it. However, he soon has to head back south so he can see Yellowstone... though he doesn't stay long, since Charley freaks out about the bears. Then, he heads to Washington.
Along the way, Charley ends up getting sick with a bladder problem, and Steinbeck tries to get him some help from a vet in Spokane. The doc isn't actually super-helpful, though. Still, they get the problem resolved enough that they can continue driving.
Heading to Seattle, Steinbeck finds the place changed a lot from the last time he was there (and not for the better, sadly). Then he heads into Oregon, where his tire blows out. Through the kindness of a dude at the one service station open in that area on a Sunday, though, he gets some new heavy-duty tires and is on his way pretty quickly.
Then he heads south through California, visiting Salinas (his hometown) on the way. While there, he argues with his sisters about politics and reconnects with old friends, but apparently it's kind of awkward, and he's reminded of that old adage that you can't go home again.
After that, he starts circling back toward home, driving through the Mojave Desert and through the Southwest and Texas. While he's in Texas, he meets up with his wife once again and stays with some friends (oh, and actually takes Charley to a competent vet in Amarillo). We get a lot of detail about Steinbeck's impressions of Texas.
After that little break, Steinbeck goes to Louisiana so he can see for himself what's going on there in terms of racial tensions (which appear to be pretty high). There was a well-known protest going on: two African American children had been admitted to a New Orleans school, and lots of people had a huge problem with that fact. So, some women known as the Cheerleaders basically stood outside every morning to scream at these poor children as they headed into school. Steinbeck went to get a firsthand look at this spectacle and was, as you might imagine, disgusted.
He then headed back home, finally deciding he was "done" with the journey somewhere in Virginia.