I have no idea what all is involved in doing the conversion to make it multi-fuel (although I'd think it would involve having to rejet the carb or another method of delivery) but would like to throw this out, just food for thought.
A few years back we had a tornado go through a very small town just to the south of our old place. Probably has a population less than 500, unless you count cattle and sheep. Power and phone poles were damaged for several miles, and service was out for almost a month in some places. All the homes are well and septic, so no water for anyone.
Many of the residents braved it out and stayed home, cooking with campstoves and charcoal or gas grills. All their food was in coolers inside. The reason I mention all this is, during the following weeks you couldn't find a propane tank for at least 10-15 miles. The ones that did have generators were driving into town to get ice for their coolers, food, and gas cans topped off for their generators. They could get gas no problem, but not so for propane.
As long as you had and adequate supply, or larger tanks, you'd probably be ok. Just remember they only have so many of the smaller tanks in circulation at any given time.