I haven't used my motorhome for ski vacations, but I have done a little cold-weather/winter camping in it.
If you have a motorhome that's set up for cold weather use (with enclosed heated tanks and plumbing), it's not at all hard to keep the plumbing above freezing while you're on the road. With a trailer, you could leave the furnace turned on while traveling, assuming the airflow from traveling doesn't cause problems with the burner--and I suspect in most cases it would not do so.
If you properly blow out the pipes with an air compressor, there's no need to put pink stuff anywhere besides the drain traps. The key is to take your time and make sure you get all the water out of all the fixtures and fittings. As a bonus, you then don't have to get antifreeze out of the pipes when you dewinterize; merely fill the water system (and sanitize if needed/desired).
(I also think it would be nice if manufacturers made the plumbing systems so they could be properly gravity drained. Granted, doing such draining would probably require that the RV be pretty carefully leveled...but other than that, it would be fairly well foolproof. Growing up, we had a sort of in-law apartment above our detached garage, the water system of which could be gravity drained relatively easily for periods of winter non-use. Draining the water heater tank was by far the most time-consuming part of the process.)