It sounds like a road trip.
In that case, you might also want to check out the Maricopa Live Steamers in Phoenix. They have one of the biggest live steam layouts I've ever seen.
http://www.maricopalivesteamers.com/
I grew up near Tucson, and I've never seen a gila monster, and the rattlers are okay if you don't step on them. Use a stick if you have to pick up something from the ground in case there's a snake under it.
The biggest hazards in Arizona are heat, sun and distance. The air is really dry, so you dry out before you know it. Keep plenty of water handy.
Don't forget sunscreen. Also, since the air is so dry, the view is fantastic. It was once a volcanic area, so the mountains come straight up out of the desert floor with very little foothills, and you can see them clearly for 30 miles or more. People who hike over to the hill on the horizon before breakfast might be walking for a day or two before reaching it.
And take your cell phone with you. The emergency number in the US is 911. Try to keep track of what road you are on so you can direct rescuers.
That should be enough basics to keep you out of trouble or to handle any trouble you get into. Coming from England, you sholdn't notice much cold, except early mornings before sunrise. By breakfast even the coldest night will normally warm up to shirtsleeve weather.
Do you know when you'll be coming yet?

Claude