An apartment size propane cook stove with a small oven is very efficient. Normal everyday usage is from 2 to 5 gallons a month. Now this is not a camp stove but a regular looking small apartment size propane kitchen stove.
These small LP ranges are available in both 20″ and 24″ widths. Five gallons of propane is commonly called a 20 pound cylinder and are used on gas grills. They are available at most any store or gas station and a single tank can last 4 months.
You can get two 25 gallon cylinders (100 pound) and hook up with automatic switch over when the first tank is empty it switches to the full tank. Hook these up to a propane stove and you have one year supply of cooking for a family of four.
This is just an estimate — as with everything survival your results may vary and you should test everything before your life depends on it.
Oh yeah…in case you were wondering if this is a real tip, when Les Stroud (a.k.a. Survivorman) isn’t 5 days out in the woods eating grubs and spiders he uses one in his off grid log cabin to cook his food.