In 50 years of hunting, camping and working in AZ I’ve lost all count of the rattlers I’ve run across. But you’re as likely to get hit by a tornado as get one in your RV, so I wouldn’t concern myself with that. As far as snakes go, don’t put your hands or feet anywhere that you can’t see. When it’s hot, they’ll be in brush or the shade of rocks. If it cools at night they may come out in the open for the warmth, especially on pavement or blacktop. So you have a clue what to watch for.
Don’t leave shoes or boots outside overnight. You won’t get snakes in them, but you might get the stray scorpion or tarantula. If you do leave them out, shake them out before you put them on. That used to be routine even inside a house when I first came here decades ago. Other than that, unless you go tramping across the desert you probably won’t ever see a snake, most people don’t.