None of the current RV's are really four season. You can upgrade them to work.
Probably a good idea to avoid slides, unless you are in one location for the whole winter.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.