You really only have 2 choices if you stick with anti-freeze. Either buy 8 or so gal of anti-freeze so you fill the water heater while you're winterizing or install the bi-pass kit. A 3rd option is blowing out the lines, which I'm not a big fan, as you may be putting stress on your water lines and I don't like the fact that I wouldn't be sure all the water was out of the system.
Days camping (2015)----88 days
Days camping (2016) ---110 days
2016 Wildcat MAXX 28RKX (33' TT), 2007 13' Scamp
2015 Ram Laramie Hemi
30 years RV'ing
12 different RV's