Most everyone here is ignoring the thermal mass of the CAMPER.
It takes more than one night below 32 to get the inside of the camper down to where water lines are in danger of freezing. Heck even in my completely uninsulated unit, the interior temperature was still in the mid 50's after a night in the mid 30's with no heat.
One night of barely-freezing temperatures is not going to burst all your lines and destroy your camper. It's when you start getting multiple nights of freezing temperatures in a row, and cloudy days where it doesn't warm up, that you really need to get busy winterizing.
