First you should know that you did not damage anything by putting anti-freeze into the fresh water tank. RV antifreeze is potable - meaning its safe to ingest (although it tastes bad and requires more AF and more money than you need to spend). You can install the Camco RV pump converter winterizing kit
for the future so you do not need to fill the FW tank.
Also, bypassing the water heater the way you did was perfect. It doesn't need to have AF in it for the winter.