Yes we have snakes here, but it is no different then snakes in the east coast. Florida has Pythons and alligators. Every state has its critters and predators. Don't worry about having snake problems. I have a residence in the edges of the Mohave desert and I have never seen a rattle snake yet. I have lived hear since 1961 and never seen a rattle snake, yet while traveling on my coach up in the mountains I have seen some. I am sure they are there, but they stay hidden most of the time. Coyotes are all over the place and they are dangerous to small pets. Saw two around the campground up in the San Diego area.
We have never had a problem with insects getting in the coach, with the exception of real tiny ants, a couple of times. I sprayed some ant poison around the tires and that stopped the problem. Other then that you will not have any problems. Come and see the west, it is very scenic.