What hes pretty much saying is every person seeking guidance and inner peace are looking for something they already have/are. And the secret to it all is nothing. Alan always says, Waking up is like walking through a door, turning around and realizing there was no door.
Most of these are not metaphors nor complicated at all. They make me pretty happy. I'd be willing to explain any of these to anyone, if you must inquire.
edit: Although I admit, that would be completely missing the point xD
Well I can't speak for Mr. Watts -- obviously -- but I understand and enjoy them. In the original audio file Alan talks about the nature and objectives of zen-koans for about 10 minutes before he tells these stories. It's a brilliant explanation, perhaps the best I've heard, but it was much too long for a youtube video and I figured it might be boring to some people.
Then I couldn't find the I that found the story.