Dbat, this post could have been written about my DD- same humor, same author love, same problem with lack of appropriate yet appealing material. Really hoping someone out there has some good suggestions for you. Right now DD and DH are loving your mention of the Oatmeal, new to us. Thanks!

Not specifically humor books, but when younger DD enjoyed Carl Hiassen's humor (though have still avoided his adult works). Would consider Bill Bryson, though DD hasn't picked them up yet, may be too slow-moving. We have enjoyed Robert Asprin (easy, quick fantasy series laced with hefty doses of humor, old so may be tough to find). She loved Hitchhiker's Guide to the Universe/Douglas Adams books, primarily for the humor. The New Yorker often has at least one humor piece per issue, plus the off-beat cartoons; both hits at our house. I will think more on it and try and pick DD's brain for more, but we have been hung up on this, too.

ETA: Mark Twain, Ben Franklin- depends on the piece (the language can be tough) but much of the humor is accessible. Some were better as read-alouds.