First: I have a 2011 Outback 329FBH. We keep her in the GA mountains on site outdoors when not traveling. We try to go south or west each winter for at least 2 months. When the forecast is below 30 degrees. AND we are not in the RV, I run anti freeze through the system. Takes me 30 minutes to do all with the adapter from CW for the pump.
When we travel through cold areas, like Texas, in Jan/Feb, we DO NOT use the water system. We prefer bottled water for ease of use for overnights. Generally we pick good reviewed parks with good bath facilities for showering.
We do use our holding tanks by dumping anti freeze in them. Does not take much to prevent freezing.
Once we are at a place we are going to be, heat on, no problems. The only issue is to ensure sudden ice cold nights do not freeze the water hose hooked from the park source to youf RV, or water in your plastic source tank which IS exposed.
There are numerous mods you can do and you will receive a ton of advice here. Pick and choose based upon your camping needs.
Most of the owners here have cold weather experience.
Enjoy. Be prepared and experiences will be not as stressful. Like carry xtra rv anti freeze