I live in Oregon but used to live in Ca. I just got information off a boat forum about Ca. being the highest state for frozen block replacement in boats because it never gets cold enough to freeze in Ca.
Bought my first RV in Ca. 25 years ago, brought it home hooked up water and when I turned it on water came from everywhere. All the water lines were cracked from a freeze that winter. Little old lady that sold it to me had no idea as her husband had died that winter. That is how I started fixing my RVs.
Yes run your propane heater at 45-50 and do not leave electric heaters unattended cause you may burn your RV. and house down.
Pogoil.