I finished winterizing the day before the PNW freeze, having gotten back from a trip the day before. We did the dry approach, but put antifreeze in the traps and a bit on top of the toilet flush valve to keep the seals from drying out. A week later, I checked the trailer and found that that the antifreeze in the toilet was slushy, like a blended margarita texture. I didn't think it could actually freeze even partially, as the temps only hit about 15 degrees and the antifreeze is rated to -50.
Glad we added it to the traps, just in case there was water residue that we hadn't blown out.
2014 28' Flying Cloud
2013 Ram 2500 Laramie Crew Cab CTD 4x4