We also have a 2016 RKX and luv it. It's our 2nd MAXX trailer as we previously owned a 24RG which was also a great TT. I would, in addition to what you've done, suggest that you disconnect your water when it's freezing temps. Use your on board water system and keep the fresh water tank fairly full. Be sure to turn on your tank heaters as they are thermostatically controlled and will come on automatically when the temp reaches 40 degrees. Also be sure you have your water heater on. You could also have your facet's drip very slowly to keep the water moving thru your piping system. Good luck and enjoy your terrific new TT!
Days camping (2016)----181 days
Days camping (2017) --- 82 days
2016 Wildcat MAXX 28RKX (33' TT), 2007 13' Scamp
2015 Ram Laramie Hemi, w/air suspension
30 years RV'ing
11 different RV's