Adding RV antifreeze is not hard just a little time is needed. So risk VS reward. Water lines will have a low spot here and there. Valves tend to hold water. Also it’s not just water freezing your trying to defeat. Drying out of rubberized parts can be slowed by adding anti freeze. Always remove anode rod and drain hot water heater also. I run each faucet, toilet and showers until I see anti freeze. Oh I always remove the caps on the low point drains and reinstall before sucking up the anti freeze. Also pour anti freeze an inch or so above your toilet valves as well. Keeps the seals good. They sell a seal conditioner just for the toilet valve as well.
Good luck and remember risk VS reward!