Silver is mobile and can be used to buy propane later. Worst comes to worst you may be forced to leave your 1000 gallons of propane behind.
“Silver is mobile and can be used to buy propane later.”
Maybe, maybe not.
Have you ever tried to buy something with silver now? I tried with gold, no takers. If you have a lot of propane, you can fill others tanks, and trade with it, though not as easily.
Where do you run to? If it is another country, probably better getting residency there now, and set up an account there with some liquid assets.
Other metals to consider are lead, copper, and brass, in useful combinations (if you can find it).