Thanks for sharing. I would agree many variables will be in play. Rivernerd, how do you pull the outside faucet inside? Your trailer is much newer (about 1,000 trailers after mine), maybe you have different plumbing. I have seen where people layer in additional insulation between the hatch door and the outdoor faucet.
In general, our experiences is as you have described. Our Oliver can handle a few hours of below-freezing temperatures each night, provided you heat the interior and monitor the driver's side hull. I was a hardcore winter camper in my youth but we will head for the barn if the temp is a hard freeze day and night