The funniest writers did not write novels. Maybe you ought to try anthologies of short humor by America's greatest humor writers. These include Robert Benchley, James Thurber, Dorothy Parker, and Stephen Leacock (who was actually a Canadian). James Thurber's A Thurber Carnival would be a good book to start with, and still easy to find.
E. B. Write (author of the children's books Charlotte's Web and Stuart Little) was a humorist. He edited a big book titled A Subtreasury of American Humor, which you ought to be able to find at a good library. It introduces you to all the American humorists.
It suddenly occurs to me that you might like the stories and novels of P. G. Wodehouse. His stories about Jeeves are the best known.