So, I went over John R. Neill's Oz stories last month. But guess what? His predecessor, W.W. Denslow also wrote Oz stories about the Oz characters. Quite simply, he and Baum had joint ownership over The Wonderful Wizard of Oz. He had the legal right to use the characters, and Baum, while quite upset that he had made such an arrangement, could do nothing about it. (Thanks for the reminder, Eric.)
A series of newspaper stories, similar to Baum's Queer Visitors from the Marvelous Land of Oz, began in 1904, written by Denslow. It was entitled Denslow's Scarecrow and Tin-Man.
The first entry was somewhat promising. It was entitled "Dorothy's Christmas Tree." Set sometime during Dorothy's first visit to Oz (seemingly just after the Wizard left, or perhaps one of the days he refused to see them after destroying the Wicked Witch), it is Christmas, and Dorothy is sad not to be spending it at home in Kansas, so the Scarecrow and Tin Man decide to do what they can to ensure a merry Christmas for their friend. (I've already chosen this as the story for the Christmas 2011 podcast, so I won't say much more.)
Dorothy doesn't appear in the later stories, so we may presume Denslow set these after her return. Only the second tells of further merry misadventures in Oz (they go ice skating with the most disastrous results), while the third finds them wanting to visit Fifth Avenue, and so the merry misadventures go to plain old Earth in the remaining tales.
The fourth and fifth tales, "About Town" and "Recaptured" were collected into a picture book, The Scarecrow and Tin-Man. Taking a bit of a turn from the rest of the series, the Scarecrow and Tin Man run away from a theater. Yes, seemingly, we went from the characters in Oz to the characters in the Wizard of Oz musical extravaganza. They cause a lot of trouble and eventually are captured by the police and made to work in the theater again.
In later tales, which resume the story of the characters from Oz (including, to a lesser extent, the Cowardly Lion), the misadventures head to the Ocean, then Bermuda. Their ship is wrecked, and they wind up in Yucatan, after saving the crew. Then, they arrive in New Orleans and take a train out west, where they are captured by Indians and rescued by cowboys before they arrive at the Flower Festival in California, where the series ends.
In these stories, the characters from Oz are quite silly and seem to have trouble knowing right from wrong, and are often chased for wrongdoings. The stories are not that great, either. "Dorothy's Christmas Tree" has the strongest plot of the bunch, and then the complexity of plots began to decrease. In fact, the last five newspaper pages are mostly illustration. That's what Denslow did best, and his writing confirms it. While Baum often tried to be funny, most notably in The Marvelous Land of Oz, Denslow relies on forced jokes and slapstick humor. (A woman notes that the Tin Man has a "hard face.")
The series lay in obscurity for many years. Hungry Tiger Press reprinted most of the stories in Oz-Story Magazine, and later, the complete series as a single book edition. When Sunday Press published Queer Visitors from the Marvelous Land of Oz, they also included all of Denslow's newspaper stories as well, allowing people to see them in their original form.
Thus, Denslow's small, silly, and very odd contribution to Oz is available today. Just don't expect too much from it!
Although he and Baum had parted ways, Denslow provided some new illustrations for later editions of The Wonderful Wizard of Oz. He designed many of the sets and costumes for the Wizard of Oz musical extravaganza and later, designed a wallpaper frieze featuring characters from the musical accompanied by verses that told an erratic retelling of the musical's plot. (It's estimated to be from 1910, so the details were likely hazy in his mind.) Aside from the Oz characters sometimes appearing in his other work, that was the extent of his connection with Oz.
Denslow, although born the same year as Baum, did not share the same bittersweet happy ending that the Royal Historian of Oz had. His success as a children's writer was very brief and by no means reached the same significance of Baum's later work. All three of Denslow's marriages ended in divorces, and his career took a nosedive. He died of pneumonia in 1915.
It is thanks to Denslow's work on Oz that he is remembered and his work has been sought out. Sadly, it was because of his own ego (and Baum's) that he parted company with Baum, which seems to have been a great mistake on his part. Yet history flowed the way it did, and we cannot know what might have happened had the two creators of The Wonderful Wizard of Oz put their differences aside and focused on working together.