At what point do you start reading a book in a new language? Do you already know say 500 words? Otherwise I'd imagine you have to look up almost every word on the page
There's also wizard of oz in latin which is a lot longer than Winnie the pooh (and more interesting), but it's hard to find and expensive, alas.
There are some really nice graded readers out there, with the entire vocabulary defined at the back of the book, and any word outside the restricted vocabulary defined in a footnote on the page. I've even seen editions that come with a matching audio book, so you that you can practice listening as well.