Douglas Gresham is the stepson of C.S. Lewis. He is also the producer of the Narnia films. I just read an interview with him in Relevant Magazine.
“Prince Caspian was a much more difficult story to adapt to the screen, because, basically, the book is all about the kids who get into Narnia. They meet a dwarf. They rescue a dwarf. They all sit down around a campfire. He tells them a long story about somebody they’ve never met. They go for a walk in the woods, and then there’s a battle. Now, that doesn’t make a good movie. We had to bring other things in and make some action happen and so forth.”
I’m pretty much just posting this here because it was too long for a Facebook status update.