This is a very simple challenge. I was not able to find a lot of information about it, but it seems to be initiated by the Hoover Dam Visitor Center. The tour consists of three caches which are easy to find. At every stage, you have to fill out a little paper with an easy puzzle on it. The boxes with the puzzle papers are easy to find and are in plain sight.
You can claim your prize at the visitor center. Make sure you check the hours of operation of the visitor center.
Unfortunately, the prize is not even worth your time. You only get one of this cheap plastic hard hats you will also get if you take one of their tours. Basically, you can ignore the prize for this tour and just enjoy geocaching around in this area. The advantage for statistic fans: you will be caching in two different states. I recommend you to take one of the tours at least (which also gives you the hard hat ;-))
Check also my review of this small geocache challenge.