The Question and Answer section for The Watsons Go to Birmingham - 1963 is a great resource to ask questions, find answers, and discuss the novel.
At the start of Chapter Ten, Mr. Watson pulls over at a rest stop right outside of Toledo, Ohio.
From the text:
"A hillbilly. Only worse. Some of 'em don't even speak English."
Hambone is a family joke. The man Mrs. Watson didn't marry.