Don't bother with a snakebite kit. If you do have to have one, get the Sawyer Extractor. I was bitten by a copperhead, years ago. The little suction cups hurt like hell but if you get to it fast enough...within minutes...it can help get some of the poison out. Worked for me, I had swelling up to my knee for 2 weeks but no tissue damage or even a mark to show where I got bit. And he got my 5 times...I only felt one little bite, like a bee sting. We were miles from the road, rough terrain and no trails, and had to stay overnight. I had to be carried out by a rescue team taking turns hauling me out on a stretcher because of the intense swelling, no way I could walk. Crutches for 2 weeks. This was in a dense southeast forest, your chances of getting bit in the desert is miniscule.
You have a better chance of getting hit by lightening, more than likely. Don't worry about critters, and consider yourself lucky if you get to see one. Snakes are beautiful creatures, especially rattlesnakes...from afar of course. Just be aware, and watch where you put your hands when scrambling around.