Amongst my people, we say Safety Third, something I learned while working for Burning Man. It basically implies that you are responsible for your own safety, so plan accordingly.
In my current life, I travel, a lot. After building and equipping my truck camping rig, (does it need a better name?) I added some safety features…
Smoke Alarm: Besides burning candles lanterns at night for warmth, I also charge lithium batteries, so fire danger is real. Smoke alarms are cheap and easy to install. I used velcro for mine.
Thermometer: I travel year round. Sometimes hot, sometimes cold. Knowing the temp inside my rig can be helpful in deciding when to forgo the camping and pony up for a hotel room. Thus far in my dry runs, I’ve spent the night in the rig at -7C, without a problem, but I wouldn’t want to go much colder than that.
Fire Extinguiser: I actually have two in my truck, one in the cab and one in the back. I placed the one in the back furthest from the point where a fire might start, by the tailgate. That way it’s reachable and can be grabbed.on the way out.
Battery Powered Fan: This is a multfacited tool. It can be used in the summer to keep cool, but will likely most often be used in the mornings in conjunction with the butane stove. I don’t plan on doing a lot of cooking in the rig itself, mostly just heating things up. But even the simple task of boiling water for coffee can emit carbonmonoxcide, a colorless, odorless gas that can kill you. A little ventilation goes a long way. I also have a CO Alarm as well.
Air Horn and Strobe Light: These two items are useful in a couple of ways. First, in case of an accident in a heavily wooded area, both items can help rescue workers find you. Second, both are useful to deter unwanted guests, human or otherwise, from entering the rig. This scenario is less likely in the wilderness, unless you are in bear country, in which case I would carry bear mace as well. But while boondocking in civilization, an air horn blast and bright flashing light are nonlethal ways to shock someone, and will also get the attention of people around you that something is wrong.
With help from my partner, we built the rig, equipped it, and are now adding features for unlikely scenarios, just in cases. Safety Third.