Most every store sells the little brass adapter to refill those small propane bottle from a big BBQ grill tank. And how many houses will have abandon bbq's sitting in the back yards when SHTF? I also bought a flexible hose to attach to make the process MUUUUUCH easier.
Handy EOTWAWKI Note: You know those big grey transformers at the top of telephone poles? Their filled with mineral oil.... It could just be possible a .22lr puts a pretty clean hole in one... Just saying....
Oh, good idea to have a 5 gallon bucket handy!
That's what I heard anyway... 
http://www.popularmechanics.com/science/energy/next-generation/4345791
Handy EOTWAWKI Note: You know those big grey transformers at the top of telephone poles? Their filled with mineral oil.... It could just be possible a .22lr puts a pretty clean hole in one... Just saying....
Oh, good idea to have a 5 gallon bucket handy!
http://www.popularmechanics.com/science/energy/next-generation/4345791