Here in 'rural' (more properly exurban) NJ, most 20# propane is sold by exchanging empty for full tanks rather than refilling. The places where tanks are exchanged (HomeDepot, Lowes, Walmart, convenience stores and gas stations) ran out of propane quickly as people glommed the full tanks to be able to cook on their grills.
However, as there are few natural gas lines to residential properties here, many homes have underground propane storage as their primary heating/cooking fuel. Fuel distributors will install large tanks inexpensively as part of a long-term contract. You can also get 100# portable tanks which are becoming increasingly popular. So propane is a rational fuel for generators as long as the distributors are delivering or you have one close by for portable tank refills.
Diesel fuel was easier to get than gasoline, BTW. Indeed, locally the same distributors carry both diesel and propane. There are a number of reasons why diesel generators make sense.
We ran our generator sparingly to power our deep well pump and keep the refrigerator/freezers cold. We refill box wine 'jugs' with fresh water and fill spaces in the freezers with 'em. When the power is off (generator not running), we take the blocks of ice from the freezer and put 'em in the fridge where they keep the food cold and melt down to drinking water with a convenient spigot.