To add to the first nitpick, the Strategic Reserve accomodates ALL U.S. usage (personal consumption AND manufacturing consumption), so if it is all accessible and well rationed out, it might conceivably last even longer than 160 days. Once the powers-that-be saw the extent of the situation, I really don't think more tanker trucks would be heading to the local QuikMart to replenish those tanks.
^I'm sure you already realise this, but I just thought I should emphasise some fundamentally questionable assumptions there.
If people everywhere (military and civies) always behaved rationally in a time of crisis then I'm pretty sure wars would have gone out of fashion centuries ago.
I have to say this is a fun discussion. I wonder what it is about these end-of-the-world scenarios that makes them so engaging when logically they should be just terrifying.