Propane questions

I’m trying to plan and decide what is worth doing and what is possible should I find myself( 70 yr female)in a situation without power and or water more than 2 weeks especially in winter (pnw winter so not super cold but gray and rain)

My house is 756 sq ft so small (single wide) I have 3 Jackery 1000 watt generators, a Mr. Buddy inside propane heater, a propane grill and camp stove. I have a couple smaller anker power packs for recharging phone, iPad,switch, kindle. I have 14 days water for me and 2 cats, food for at least a month.

My biggest question concerns propane- I don’t use it often, not a camper or griller, but I am thinking of getting 2 20lb tanks (prefilled) to have on hand. The propane heater at 9000 (mid heat) should last about 44 hours per tank (I estimated 18lbs). unless it is super cold I think that should last me about a week, heater will warm 445 Sq ft I have warm clothing and I can shut room doors.

Apologies for the long intro - Now the actual question-

if this went on longer than 2 weeks and some emergency services became available would propane be available through them and if I get like blue rhino tanks can they be refilled in a situation like this? Should I get a 3rd tank? The Jackerys can be used for heat in emergency but not for long, my little space heater is 500 watts.