Eating mushrooms make you big and strong!
There are medical supplies, money, weapons and ammo laying all over the place. All someone has to do is go pick it up.
Food laying on the ground is extremely good for you.
Generally, you do not have to actually pick up the items laying on the ground, just walking over them will pick them up for you.
If you cannot find supplies randomly laying around, then blow something up. Usually there is good stuff hiding inside of other stuff.
You can walk into anyone's house, take whatever you want, and they will not stop you.
Beware! Ninjas are everywhere.
If you talk to enough people, they will know how to find what you need.
And finally, sometimes, you can never go back.
So beware world! With these skills I will not only survive the apocalypse! I will rule the post-modern world!!!!