Northern Arizona has a lot of cinder and sharp basalt (hardened lava) as the region used to be very volcanic. I often have to kneel on hard ground, rocks and even fallen trees. I’m no spring chicken, and this hurts my knees. I’ve found an easy and inexpensive solution to this problem that you can use too.
While most of us don’t live in our cars, some of us may sleep in our cars, or RVs overnight when going out on a shoot. Before you do this, check out this article by Nicole Jordan. Two years ago she chose to live out of her car and travel the country. In the article, she lists 17 things she does to stay safe. These tips are good for people who are spending the night in a car or RV, or are even parking at a trailhead to take a hike.
Two things I would add are buying a tool to break a window and cut a seat belt. They are cheap and can save your life. Also, you can set off your car alarm if you are threatened. This will grab the attention of everyone in the area.