We filled up the tank on our Sunseeker motorhome and traveled for 14 days and over 2000 miles with the refrigerator running on LP gas. When I later went to have the tank topped off, it took so little that the gas station didn't bother to charge us for it. In addition to the refrigerator, we sometimes used the stove, and we used the water heater a few times, but never used the furnace (it was late June). We were plugged in most nights and it wasn't using LP then.
For your information, the furnace is the LP gas hog. If it's freezing cold and you keep your camper warm, the furnace could easily use 10 pounds per day. (A 30,000 BTU/hr RV furnace takes about 2 pounds per hour. They are not as efficient as newer home furnaces.) Take an extra LP tank when it's cold.