I would guess if your fresh water tank is inside your Travato that most all your water lines would be as well. So if you can keep your inside above freezing you will be OK. About the only thing you would have to do is periodically put pink anti-freeze in your floor waste trap (after use) and maybe add some in your grey and black water tank. If your daytime temperatures go above freezing I would think you would have no problem with dumping. Of course, staying ahead of the cold weather seeking warm climes is what full-timing would be about I would think. :)
I wouldn't winterize the traditional way such as emptying tanks unless you plan to deliberately stay in or travel through all day below freezing weather. If you want to see how one couple remodeled their B for cold weather camping and get their ideas, read the blog,
The Fit RV. They insulated water lines, routed heat next to them, put heating pads on under floor waste tanks and heating on the discharge waste pipes to keep them from freezing up.
We don't heat our B overnight other than to keep it above freezing. Then we open cabinet and bathroom doors to put what little heat we have in those areas. We use sleeping bags good down to 20F. We have camped in overnight temps as low as 18F but would plan to avoid anything colder. It is hard not to avoid that situation in the high elevation Rocky Mountains in September.
