Staying warm is one of those "It depends..." things.
It depends on how cold it is outside.
It depends on how well insulated your rig is (but they're all relatively poor).
It depends on where your water tanks and lines are, whether they have supplemental heating pads.
It depends on how warm you want to be.
If you're going to hit the teens (*F) as a low, and hit them rarely, then there are some pragmatic things you can do to keep the water from freezing and stay warm. It'll take some money to buy some supplemental things, and yes you'll want to be someplace where you can plug in (or run a generator). And you'll want your propane tanks full.
But an occasional drop into the mid teens wouldn't be a deal-breaker for me. There are solutions.