A 554-page paperback novel that came out in 2007 was Halloween In Oz: Dorothy Returns. This is the first of the Alpimar Books Oz series by Leo Moser and Carol Nelson, and published by Whitfield & Dodd Publications. It is a direct followup to the original Wonderful Wizard Of Oz, although it is technically an extended retake on Marvelous Land Of Oz.
Taking place about a year after Dorothy first went to Oz, she tries to convince her friends that Oz is real, but at the same time she keeps having dreams about her dead parents speaking to her through a photo of them she believes she left in Oz. After finding some magic ribbons, she ends up in Oz(a second time)where she learns that its Halloween which lasts 13 days there. At this point, it basically becomes Land Of Oz, but all the new characters' names are changed. Tip is Mitt(who also resembles a boy Dorothy knew from Kansas), Jack Pumkpinhead is Punk N. Head, Mombi is Salmanta, Jinjur is Ginger, and Sawhorse is Stubs. A few other characters who weren't in Land Of Oz show up here too, like "Fearless" Lion and the Good Witch of the North.
The book tacks on a slighty different ending to that of Land Of Oz as to who turns to be Princess Ozma(or "Esmera" here). But, if you really enjoyed Land Of Oz then you might enjoy this version of it, even if its not around Halloween.