Blowing out water lines prior to winterizing

Drain the water heater and bypass, pull the low point drains and open all valves to let all the water drain out. run pink through all the lines. then dump enough pink down the drain(s) to flush out the water. don`t forget the toilet and shower hoses also.
RV antifreeze can be bought for $2 a gallon on sale. that's less than $10 to guarantee nothing will freeze and burst in the winter. No one can guarantee that with blowing out only!