The two versions I have are the 3:15-long one from "Now We Are Six" (here on YouTube) and the 6:48-long version from "A Rare Collection 1972-1996." The longer version keeps the "moral lesson" lyrics about the road to Elfland, but I have to say the instrumentation in the 3:15 version rocks.

There's another long version here which has pretty lush instrumentation, and I might recommend that one except that I have no idea what album it's off of. If you figure it out, let me know.