What I would want to talk about in relation to the theme of hope in this excellent novel would be the setting and the way that Bud's adventures and the people that he meets offer a counterpoint that offers promise of something better compared to the harsh realities faced by so many during the Great Depression in America during the 1930s.
Even though the description that Bud gives us of the kind of places that he goes and the people that he meets shows the dire impact of poverty on so many, the human spirit and compassion is shown to remain unextinguished and still very much alive. Consider the "pretend family" Bud picks up who, in spite of having their own children, give Bud their portion of brown sugar to go with his breakfast. The residents of the Hooverville where Bugs and Bud spend some time feed them and look after them, and then finally Bud finds the home that he is looking for. It is perhaps ironic that Bud experiences more human kindness in his ventures as a homeless boy than he ever did whilst he was being cared for by the state. Hope, the author seems to be saying, is very much alive and present in this otherwise bleak period of history.