The UK version of the review aggregating site Rotten Tomatoes had a chance to talk with Wes. Below is an excerpt, read the full interview at their site.
You spent some time while you were writing in Roald Dahl’s hometown, what was that like?
WA: The place where we went is called Gypsy House, which he bought later in his life, but it’s where he wrote many of his best-known books. Mr. Fox was written there, certainly. We were interested in the idea that we wouldn’t just base it on the book; we’d base it on him. He’d written memoirs for children — which is an odd thing, not many people have written autobiographies meant for children — so from that point of view we were always very aware of him and aware that kids reading his books didn’t just know the books, they knew him. We tried to get as much of his personality into the character, and we also had his manuscripts. In fact, we had the manuscript for Fantastic Mr. Fox, which had a different ending which we used in the movie. That’s a great luxury — to be able to say, “Here’s an idea we can use — it’s not in the book, but it’s from him.”