Hi,
So, you're off to the bright lights of Las Vegas? I'm sure you'll have fun. The city treated me well during my 11 years there.

I wouldn't worry too much about your dogs. Certainly the risk does increase if you let them run wild in the desert (because you are potentially exposing them to rattlesnakes) but for typical housepets they should be quite safe.

Most people hire exterminators once a month to get rid of any black widows which are apparently quite common. During my stay there, I never saw one although I wasn't exactly looking for them. However, none of my three dogs found one either.

I remember only three particularly nasty snake or spider bites. Two were dogs and one was a cat. All three survived with just supportive care. So you can see that the risk is quite low.

I think you'll have a lot more things to worry about. Like, why in the heck are you moving to Las Vegas in July when the temperature soars to 115 degrees??

Good luck!
drphil