I arrived at Phantom Ranch by mule, the only other way is to walk in, so by design it's a pretty exclusive world. The cabins themselves are what could be described as rustic and have only a sink and toilet -- the showers are in a separate building with towels provided (you don't need to carry them down).
It really feels like another world, maybe Brigadoon, because although there is electricity there is no real contact with the outside world. You can put down that Blackberry with no guilt! After arriving (and totally exhausted), we took a walk to the nearby river and took in the spectacular. there is a quiet comraderie with everyone you pass knowing that you've done something spectacular and made it to the bottom.
Don't expect luxury, that's not what you are there for -- the mattresses aren't great and the steak dinner was just about raw (I know, I know some people love it) -- but who the heck cares?
We signed up 4 months in advance and were apparently lucky to get in, so if you haven't reserved in time, still give it a try.