[HairOfTheDog]

I think the West entrance was not always so narrow and hard to get to. The river that flowed out of it had been dammed up (by the watcher in the water) causing the lake that flooded the valley up to the door, and the stairway was probably not always treacherous, but had fallen into disrepair...

[doubled]

But it was dammed up after leaving the mines, so it shouldn't have affected the path on the inside. If I remember correctly (and I don't have my books to reference) the trail was a narrow path along the side of a cliff for quite a ways. I was a little disappointed in the movie when they entered and Gimli was carrying on about the greatness of Moria with the skeletons around their feet. A small departure from the book. Gimli held hope of finding the colonists until they found the diary and tomb.