They are shy and retiring, only get above ground a couple of weeks a year, and bites are rare. The good news about a Gila monster bite is it takes time for them to work the poison in. The bad news is that once they latch on it's hard to make them let go. Left alone, they are harmless and afraid of humans, but if they have to defend themselves they can be fierce. If you see a herd or an individual, enjoy the sight but don't try to get closer.
Mountain lions live here, and black bears can be encountered in the higher mountains.
You can save some money by buying the slime and putting it in yourself if you have schraeder valves and a valve core remover. The comb is the best way to remove a cholla cactus, because the needles go both directions. Carry this with your gear. If you have a close encounter with a prickly pear you will have dozens of tiny, hair-like needles. The best way to remove them is coat the area with glue, let it dry and peel it up, needles, hair and all.