I doubt I'm the only illustrator to hoard sketches. It's a bad habit. I feel like I'm constantly wading through paper. But it's hard to throw away those first scribbled ideas. Here are a few pics that might be of interest. First, the storyboard... this changed quite a bit before we settled on the final layouts but this was the first version.
And next, the end papers. End papers are always such a pleasure to produce, and I've added as many stinky, squelchy details as possible.