IMO, don't put antifreeze in your fresh water holding tank. It will take you forever next spring to get it all out. Do a complete winterize, including draining your fresh water tank. If you're going to do some cold weather camping, bring a couple jugs of RV antifreeze, use it to flush your toilet. Just my option, even though I don't do the cold weather camping.. others that do might have a better suggestion.
2015 Rockwood Windjammer 3029W Diamond Package
2014 RAM 2500 Laramie Longhorn 4 x 4
6.4 Hemi 410 HP, 410 Rear Axle