Portable backup Coleman ProCat heater for your camper

When we got our Coleman Cedar popup camper it came with a Coleman ProCat heater because the furnace was not supposed to be working, but it did. We used it several times in place of the furnace to save battery power and in our 8' popup it did a good job heating it putting out 3000 btu's, but the 1 lb cylinder wouldn't last over night on it's lowest setting. We tried it in our 30' fifth wheel and it would take the chill off but 3000 btu's was not near enough no keep it warm especially at 9000 ft plus.