Why do I care about the energy equivalence of propane vs. gasoline?

This will be the first year to use the Coleman propane stove I acquired.  In previous years I've used the dual fuel (Coleman fuel, which is white gas, naphtha, about 50 octane, plus gasoline).  I would typically use about a little over a gallon during a week camping, which includes breakfast coffee (actually, milk steaming and espresso), breakfast pancakes, some fairly sizable dinners, and the occasional hot water for tea.

What should I expect for the propane stove?  Well, now that I know the roughly 6lbs propane = 1 gal gasoline, then I should expect to go through about 7 pounds of propane during a 1-week stay at a campground while cooking for the family.