I started to test my system during off peak times of non use.
Some rv's freeze in areas that others don't. IMO, simple individual testing might be an advantage for you.
It's not a foolproof test but it made me feel better. I now feel more confident in my system because it seems to be more forgiving that i thought. Since 2004, I have tested Arctic Fox, Lance and Jayco .
*** During storage periods of non use, place bottles of water in various areas of your unit as a test to see what or where things freeze on your particular RV. Address those areas with extra insulation.
Each individual person is going to have test their particular unit, in their climate and monitor the temps, keep a log.
I have found the water bottles that i placed inside the RV (next to the toilet and water pump under the kitchen sink) took much longer to freeze than bottles placed outside exposed to direct wind.
Water bottle placed outside on the bumper did freeze but interior bottles did not.
Water lines inside the RV have some flex to them but the toilet components and water pump can crack . Being those are expensive items to replace, you should try to protect them but the temps have to pretty low in order to penetrate to the interior of the RV.
Once you know your RV freeze point better, you will know what to do while on or about to take a trip in borderline temps.
As said, its quick and easy to blow out the lines and drains, but protect the toilet, water pump, black tank rinse and outside shower if you do that. Blow out the black tank rinse line if you have one.
While on the road :
If you park (the rv's dry side like the bedroom with no water lines ) heading into the wind it might help to protect the rest of the rv water system.
I was concerned about the water lines that run along exterior walls so i did my best to wrap them in pipe insulation or simply move them off the wall . ( reposition them if need be )
If you find that your particular RV is prone to freezing , it only takes a few minutes and a gallon of pink stuff to shoot some rv antifreeze through the entire system and allow it to drain out right away so there is no residual antifreeze in the system to effect taste. It fully protects you and makes it fast and easy to refill and be back in business the next day.