Just popping over to the nearest parallel dimension, won't be a minute

Finished Caspian. Guess what? The end was as boring as the rest.

I started Voyage of the Dawn Treader, and thanks to some lengthy downtime in which I was unable to use my work computer at all, I'm now 4 chapters in.

According to Wikipedia (and I know what you're thinking - it MUST be true!) J. R. R. Tolkien did not like the Chronicles of Narnia because "he disapproved of stories involving travel between real and imaginary worlds." I think Tolkien was being nice, and didn't want to say that Lewis is just not that graceful with the whole "travel between the worlds" thing. I've read plenty of stories and seen plenty of movies with travel between our world and some parallel dimension, and they usually play out just fine.

That has everything to do with presentation; your hero can't just walk by the crack in the wall in chapter 1 and say "I say, that looks like the Faeriey* World over there! I think I'll just pop over and see, although I've no motivation for such a journey!" The movie cannot open with Sarah saying "where is the baby? Good grief, there's a mystical labyrinth in the back yard! I'm sure that David Bowie has stolen the child! I must save it from the evil muppets!"

Meanwhile, Voyage of the Dawn Treader, Chapter 1, just barely paraphrased:
Lucy: Look at that picture of a boat, Edmund! It looks just like a boat of Narnia! Oh how I do wish we could be in Narnia right now!
Edmund: I say, I've never seen a more Narnian boat! Blimey, the picture is moving!
Lucy: Cor!
Edmund: I'm certain this picture is a portal to Narnia! Put down those crumpets, Lucy, and let's just pop in and see!
Annoying Cousin: You and your stupid Narnia!
Lucy: Even though you are a ridiculous prat and the author is using both you and your parents to represent people he hates, I feel very sorry for you because I am the sweetest little girl in all of literature!
Annoying Cousin: Oh no! I've come through the picture with you, and now I'm in Narnia! Here I shall surely get all the punishment I deserve! It's all your fault, Edmund and Lucy!
Edmund: That's your majesties to you, blighter!

But what the hell. It's easy reading, so they go by really quickly if I don't get distracted.

*intentional misspelling of "fairy".