I went with a group of young boy scouts on this hike in mid-November. It was a cool dry day, so the hike was much easier than expected. Not as steep as anticipated either. But, 3.9 miles each way left me sore for the next couple of days.
The river was much lower than shown in this pictures. This left much of the white marble rock exposed. The boys enjoyed scrambling on the rocks. I'll go back when the river is higher, but I recommend going when you can see why it got its name.