I am not sure how to approach this....as I too own a "cold weather" packaged Work & Pay ( yes work & pay )
At no time was this trailer represented to us as a 4 season camper, not by the dealer, the sales rep, or the factory rep we talked to (either by phone or in person during the factory tour). in fact it was quite the opposite, they all cautioned us to not expect this to be used regularly in hard freeze conditions for any amount of time. They advised no more than 24-48 hours sustained temps below 30 degrees.
That being said, i had ours stored outside most of this winter, and did have the furnace on, and water hooked up for a couple of weeks, just to test things. It performed as expected. used alot of fuel, but the 30K BTU furnace kept up fine, actually did better than well. as we stayed toasty while performing some interior upgrades. Once the weather dipped below 25 degrees i put it inside for the remainder of our modification process.
Maybe you all bought from bad dealers, or had a bad factory rep, I'm not sure. I do know that dads advise hasn't ever steered me wrong, don't pay the man until you know what he's sellin'....
2012 Ram 3500 DRW G56