Using over the winter - do I need to winterize

You have a third choice. Do a full winterizing job (I'm in the air-blow-out crowd if it can be done on your rig.) When you go on a winter trip, don't use the on-board water systems except for the toilet, for which you dump some pink stuff in along with your carried flush water.
Sort of like tent camping, but you have your warm rig and a toilet along.