Don't forget BLEACH - common and easily used. Do like I did and pick up a used 55 gallon food-grade drum (mine was found at a surplus store being sold for a paintball field) and run it full. My barrel has the faintest smell of pickled peppers (what the container originally held) and that computes to about 1/4 to 1/2 cup of bleach to preserve it. Store it in the shade and you're set for several weeks.
It also helps to have a fresh water supply close by - don't underestimate local resevoirs, ponds, golf course ponds, etc. as potential water sources (assuming of course you can purify it somehow).
A mention about the salt water conversion still - 2 things there that make it less than ideal - first is the amount of energ you need to produce to distil the water. Makes it less appealing unless you have an unlimited wood supply or something to keep a furnace going. Also, chemical contaminants that have an evaporative point lower or equal to water may be an issue. You'd distil that AND the water. Something to consider.