oldcarguy, the water heater in our trailer uses very little propane. I always run our water heater, as well as the refrigerator on propane, even if we camp in a place that has electrical hookups (which is rare, since we prefer boondocking). We've been out for about two weeks, using propane for some of the cooking that we might do inside, as well as hot water, the refrigerator and now and then the furnace if it's cold, and we've NEVER had to fill a propane tank. At the most, one will be empty after the trip, but the other will still be supplying gas.
Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH
2014 F150 Platinum 4x4 3.5L EcoBoost SCrew