I live in the Greater Cleveland Area, though I've done quite a bit of Vegas-area herping. You can see my pics at:
http://www.thirdeyeherp.com/spuck/vegashome.htm
Hopefully that will give you some ideas of where to go. May is a very good month for finding stuff.
I will probably be herping Vegas in the first week in June. If you're interested in going herping with me when I'm there, let me know. My e-mail is:
tim@thirdeyeherp.com.
Tim