Hi Triplets,
What part of Arizona would you like to see? If you staying up around the Grand Canyon then if you haven't been to Sedona yet there are some great
hotels and resorts and beautiful natural features. Do you like the heat? anything outside in August will be very warm with Temperatures ranging from 90–120°F (32–48°C), the kids may enjoy a resort with a pool.
As far as snakes Arizona is the right place to go. I recall there are about 60+ varieties of snake of which 10+ types are poisonous (be careful). One interesting sightseeing destination may be the
Montezuma Castle Monument located between Phoenix and Flagstaff. Then heading toward California Lake Havasu is another nice location on the Arizona California border.
Check out the
Arizona Map for a better idea. Since I noticed your post in Las Vegas as well it seems you could make a nice loop out of your trip. In California you could spend a day at Joshua Tree. All in all that section of Arizona, California, and Nevada is pretty dry so mixing that in with some hotels with pools may be a good idea for the kids.
Write back with some more details and I'm sure we can help.
Cheers,
Dan