im not in the southwest but i am from kentucky and boy do we have a lot of snakes! most of the time when i encounter a snake while camping or walking through the woods i just stand real still and in a few seconds the snake wiill generally turn in the opposite direction. at night they look for warm places and in the daytime they look for cool places like bushes and the shade of fallen timber. they really love low lying swampy areas and in places where a lot of driftwood is piled or fallen branches. you should always be carefull in the mornings when you wake up and walk around your tent especially if you had a campfire the night before, the snakes tend to like warm rocks like the kind that go around a campfire. always check your gear cautiously, sometimes its better to use a long stick to kind of punch your gear and see if anything moves inside it. snakes are very unpredictable. but the main thing that a lot of people dont know is this,,, snakes are more scared of you than you are of them. they will rarely strike unless they feel like they are in danger or theyre guarding a nest. it would be a good idea to carry a long stick with a forked end so if you were in a situation where the snake didnt leave but charges you , then you could pin it down with the forked stick and cut its head off. but a snake will rarely attack. as of scorpions i dont have a clue. ive never dealt with those critters and hope i never have to... hope this helps a bit..
ROBERT JENKINS