I did a little UYE hiking action with Norm K and August C last weekend. I won't reiterate all of the useful information that Norm has already listed. If you need directions to the trailhead, I refer you to his excellent review.
I found this hike to be pretty easy. There is one scramble down (and back up) a 15-foot spillover in the wash. Other than that, it's a very gradual descent toward the Colorado. You don't actually make it all the way to the river on this hike. There is a 25-foot dry fall that basically serves as the end of this out-and-back hike. Even if you decide to brave that drop, Norm says there is a 300-foot drop waiting for you just moments ahead of that.
Instead of pressing downward, we backtracked and found our way up to a ridge where we had a great view of the river and the Hoover Dam bypass bridge. All told, we hiked about four miles. Of course, the hike could have been longer if we didn't drive the two miles down the wash until the point where they prohibit vehicles. That's probably the one thing that would prevent me from doing this hike again. Most of the "road" is fine, but there may be parts where having a 4x4 is recommended.
I probably won't ever do this hike again, but it was an enjoyable morning and I'm grateful that I can cross it off my (nonexistent) list.