One of the things I have always suggested as preparation for a disaster is camping. Someone who camps a lot knows what they need and they usually have it around.
If a disaster happens people who are used to doing without and/or people who are used to scrounging what they need will survive. Women between 10 and 50 are most likely to survive, people with families or unified groups are more likely to survive than people on their own.
There are always exceptions, but, these are the basic statistics.
So what do people need to survive? Water, food, clothing, shelter, heat. Keep those things in mind and prepare.
Plastic sheeting and contractor grade plastic bags are two things everyone should have stored for an emergency. People should have enough heavy plastic sheeting to wrap their house. No, people are not going to wrap their house, but, having enough to means that if the roof blows off or a tree falls through the walls people can do something.
Contractor grade plastic bags can be used as ponchos, sleeping bags, vapor barriers, and a bunch of other things.
Bleach is awesome. Keep a gallon or two around for emergencies. Filtering water could be important so having fish tank filters (unused) can be useful. After filtering water can be treated with bleach. People can make their own filters using charcoal, sand, cloth.
There is a company called "harborfreight.com" which sells 12v water
pumps. Hook a pump up to a Culligan filer assembly, three filter
containers, one with a coarse 20 micron or more filter and one with a 5
micron or less filter, finally a carbon filter and the water is pretty
clean. The water is not pure though, so add some bleach to treat it or
distill the water after filtering. If the contaminant has the same
boiling point as water you are sol.
A distillation system can be made with an old pressure cooker. Drill a hole for about a 2' pipe fitting in the top of the pressure cooker and let the steam flow into a condenser of some kind. A feeder tank can be attached to the pressure cooker with a copper tube. Pour filtered water into the feeder tank, water flows into the heated tank (keep temperature around 200), water converts to steam and is condensed back into water. If someone is worried about other contaminates they can add a second, low temperature heated tank to boil off stuff before it goes into the second heater tank with the condenser.
The first time I built this kind of distillation system I tried using a 3/8 copper tube for the condenser and the feed line, Pressure built up in the tank and pushed the water back into the feed tank. This worked okay, I was still able to distill water, but, most of what came out of the condenser was steam. I made a condenser with a much larger volume, that reduced the pressure in the tank and more water came out. There are a lot of minerals in tap water, the heat tank was pretty filthy after I had about a gallon.
I also have an extra 12v battery I keep on a good trickle charger. If the world goes to crap I have a power source. A 12v motorcycle battery is cheap and is usually sold with the acid separate from the battery to increase shelf life. Put the acid in and it is charged up. I suggest having a 12v cigarette lighter receptacle to attach to the battery.
Solar chargers can be useful, unless the sky is overcast because of the disaster. There are things you can put together to charge a battery. Most 12v motors can be used as generators. This can be kind of tricky for a novice to hook up, so if you want info on how to use a 12v motor as a bicycle generator look it up on line. a 12v LED bulb is really useful too.
A portable CB is the shiznik. Yeah, I know, it is really "Live free or Die Hard", but, the writers had that one right. In the military we used to say "shoot, move communicate". We have to be able to shoot, move and communicate. Moving and communicating are most important, shooting attracts attention. Too many survivalists or preppers put way too much time into guns. Shooting is important, but, on a list of critical things shooting people is way down the list.
Selfishness is important to survival, or so analysis of large group survival situations tell us. Cliques form and they strip other cliques of resources. Then they kill and eat each other. It takes a while, from a couple weeks to a couple of months without resources to get to that point. By then I plan on being dead.
Until things get that bad though, I could have a pretty good time hanging around.