I used to work in the field all the time for a living in places like AZ, NM, Utah and Nevada. Snakes are around but you will see few. Be careful when temperatures are 70-80 degrees. During the heat of the day they are in the shade. At twilight they come out of hiding. By early morning in the cool weather they are sluggish. Step heavily and shuffle your feet in the brush. I carried a shovel a lot. Carry a stick instead. Keep your eyes moving and be careful where you place your hands and feet.
I have almost stepped on several of them when doing plant surveys. I have had one crawl under me when sitting. Do not disturb them and learn their habits.