GREAT hike! Loved it and it is not listed on typical hikes around Lake Mead. This one you have to kind of search for, but it is absolutely worth it.
My husband and I came out here with our lab around mid-morning on a Sunday. We have a Jeep so we drove up to the area that forks right and down a hill in order to get to the hike. We parked and walked down the dirt road. This road leads down into a valley area where you begin to see all of the left-over mining remnants from when they were mining Borax in this area. You can see where the carts went through the mountain and there is a large mining opening in one of the mountains you can walk up to and look into it. There are pieces of steel here and there and you can really see in the mountains where they carved it up. Interesting to see.
You keep walking and eventually get to the Narrows hike, you'll know it because there is a "Wilderness" pole in the ground in front of it. Once you get to the opening, you can continue through and it's a neat experience to be able to basically walk through a mountain. It isn't very long, eventually you end up outside again where you can see much of the rocks that get pushed through during flooding.
It's not a long hike, there are some places you have to pull yourself up over some boulders, but nothing too strenuous. When we were there we encountered a family with small children, and even they were able to make it all the way through the hike.
Overall, a good area to explore and spend a few hours of your day.