Very beautiful hike that's not too much of an effort. Great for kids and out of shape hikers like me.
The trailhead isn't marked but it's pretty obvious where the trail starts. In case you don't see it, it's around the second (middle) picnic bench. You have to go down a very steep hill that has pretty loose gravel. This is the most "moderate" park of the hike.
Once you get into the slot canyon, it's very easy to ambulate. Some small obstacles but not many. There are many shaded areas if you decide to go during the summer like I did. It was 9am but it was still pretty darn hot.
The culverts are an interesting portion of this hike. It is a bit dark inside the longer (first) one but I didn't use a light and was able to see pretty well. And believe me I was looking. Snake + solo hike = no bueno.
I didn't follow the advice to loop around, I just turned around where you could loop around after the second set of culverts [this will be pretty obvious too because it the only section that looks kind of like a ramp on the left side (SE) facing away from the culverts] because I wanted to walk through that slot canyon again.
As of 6//17/18, the entrance fee to Lake Mead was $25 for 7 days. However, if you live here like I do and you think you'll come more than once, it's probably best to get the $45 all year pass.