I truly don't understand the gold/silver thing. Maybe for a few weeks if people lose faith in currency or in a short term disaster with a foreseeable end an opportunist with good stockpiles might trade for it to make a quick buck, but it has no usefulness outside of it's perceived value. In a true EOTW situation I wouldn't trade a can of lima beans or a round of ammo for a pound of gold.
you are thinking small scale. fuel for a r22 will cost a S load of your canned chicken. People with enough money to survive.. i mean the people that are like super loaded will have safe places to go. Also, once all the middle class and low class kill off each other the upper class will come out of hiding, re build and still trade on gold and silver.