This is a 2+ mile one way hike from the trail head to the Colorado river.
From Las Vegas, you take exit 2, right after Hacienda Hotel on I-93, you then turn right and immediate left onto dirt road to the trial head about 1/4 mile down the road. The first mile is a gentle easy downhill hike in the canyon bed, then it becomes scrambling through large boulders, using ropes in some places. You get to the upper pools, but there seems to be only one that is bathable, and rest seems to have gone dry.
There are some middle pools further down the trail, and then the most rugged hiking/bouldering/scrambling is from the middle pools down to the Colorado river.
It is quite scenic, and scrambling/climbing/roping down over boulders is quite fun. It is not particularly physically demanding if you are in decent physical shape. We took kids as young as 7 year old who needed moderate amount of help, but teenagers should have no problem. It took us 2 hours exactly to get down to Colorado river and just as long coming back up.
Overall highly recommended fun day hike.