Out of all of the classic ways to get pulled into another world, which is your favorite? Accidentally walking through a magic portal (rabbit holes, wardrobes, mirrors), being summoned there by something on the other side (magic, teleporter, whatever), or you wake up and find out that it wasn't real at all (dream, coma, drug-induced hallucination)? Or some other way I haven't thought of?
Many of my favorites that I discovered as an adult fit that mold as well -- Phantastes, Lillith, The Chronicles of Thomas Covenant the Unbeliever, and even A Princess of Mars.
My two favorites would be some form of portal -- and I'm partial to wardrobes and mirrors -- and just waking up in the new place like Thomas Covenant and John Carter.
Why? Because in both settings, they quickly get the method over with so the writer can get on with the actual story. I know some readers who love to get all the technicalities of the method perfect so that the "reality" of the method is solid, but honestly, in a story about traveling to a "magical" dimension, that's just not very important to me as a writer or as a reader. I want to get from point A to point B so that the characters can get on with their discoveries and adventures.
That's just my opinion. Your magical clock door may lead you to different opinion.
Thanks to Sarah White for today's question.