This is a guy who guards a property somewhere in the Midwest where Steinbeck decides to park. They get off to a rocky start when the guardian tells Steinbeck that he's trespassing, but after Steinbeck charms him and offers him coffee, he mellows big time. He ends up inviting Steinbeck to stay, and they even go fishing together the next day.
According to Steinbeck, it's no wonder the guardian softened, since he seemed a bit starved for human company: "The guardian of the lake was a lonely man, the more so because he had a wife" (2.5.80). Hmm, that's weird—why would a wife make him feel lonely? Well, it seems that "He wanted his pretty little wife and he wanted something else and he couldn't have both" (2.5.80), and he would pine for this undefined "something else" forever, in Steinbeck's assessment. Brutal.