I'm glad I saw a woman crawling out, because I probably would have just peeked in from above, and called it a day. If you're fairly limber and strong, go ahead and climb in. It turned out to be really interesting inside. The ceilings are very tall, and it's interesting to look up at the sky and trees through the crevices. I expected there to be ice, but there wasn't much at all ... loved the sound of the trickling water though.
And for the sound of waterfalls, continue up the path to the cascades. It's a fairly easy, short hike, and so worth it to be near the power and beauty of that water.