The Original Adventures of Hank the Cowdog, by John Erickson, Puffin Books, 1999.
Full disclosure: I didn't buy this book. A friend of mine bought this book and three others for my son. But she bought them because she remembered how we used to read them out loud and laugh at them at work. (Oh, we were both children's librarians, so it wasn't as weird as it sounds.)
This book was pretty darn funny. I'm not sure that my son caught all of the humor, but a few times he laughed out loud, and he understood the plot. Good enough for me.