Don't forget the low drain points for the water lines.
BTW, I do the blow out of air lines, open the water heater and then open the low points to drain. The pink stuff only gets added to the trap and toilet bowl. I've not had a problem yet.
I've also never been able to fully drain the fresh, gray and black tanks completely. I do as good a job as possible and leave it at that. So far, so good.
I was surprised to hear Lancaster had to winterize too but better safe than sorry.