Actually, in a crisis scenario where there is an extended break in infrastructure and/or utility services, by the time the event happens the time for getting fuel or anything else will be, for all practical purposes, gone. That's why it's so important to ask those questions to oneself now so that you can assess what you would need to do now pre-SHTF to prepare and ensure you were able to continue having sources of fuel to cook food.
In that line of thought, you have several options, i.e. buy a coleman stove and several gallons of Coleman fuel like one uses when camping, or buy a single or dual propane burner, or better yet, a propane BBQ grill and keep several 20 lb. tanks of propane on hand. There are other options as well. It just depends on the option that works best for that individual.
How does one plan for the long run, like >6 months or so?
I am thinking more of a steady decline and huge hyper inflation.
The Surviving in Argentina blog is very educational in this respect. And those of you who aren't on the back 40, don't be discouraged. Ferfal (the blogger who lived thru the Argentina crisis and still does) says rural areas can be very dangerous too. He says the safest set up is an area of like minded folks who can take turns with security and guarding the fortress. The biggest problem will be looters and roving bands of people looking to take advantage. Argentina saw and still sees this very much in the rural areas.