If you have a Coleman stove that works on the small propane canisters, you can readily adapt it to work off a five- gallon propane tank. This lets you run your stove almost 20 times longer without refueling. It takes a simple adapter that is sold by Coleman for $9.99. The adapter goes between the hose and the tank. You can also get an 8 ft hose so that your propane tank can be set further from the stove.
It is cheaper to buy your propane in the larger tanks. The main advantage of the small tanks is ease of movement. Personal it I have to bug out and were to take a Coleman stove, I would be leaving by vehicle and the 5-gallon propane tank would be easier to load.
My experience with a Coleman stove has been good. I have always found them to be reliable. If you have multiple 5 gallon tanks stashed you could cook for quite a number of months. Because we would use it in conjunction with a Sun Oven and a Wonder box, it is hard to give you an estimate of just how long the propane would last.
Propane is one of the easiest and safest fuels to store as long as you use some common sense and follow the rules put out by your local fire department.