portable air tank,and a water line blow out plug( any camper supply) think even Walmart has in camp/RV section in automotive. I open up all inside faucets H & C. and just about 10 PSI not a whole lot of pressure from air tank, to blow lines clear. Drain the Hot water Heater, always have the Black and Grey water tanks clean and empty. the pour the RV Pink Anti Freeze down in each sink and shower/Tub drain, and I leave some in the commode bowel, as not to let the slide flap get dried out. also speaking of toilet be sure to flush the water line to it while doing the sinks etc mentioned before^^. some forget that water line and have a freeze and or Bust of its line and even the flush valve. I never use the fresh water tank in any RV or TT ever had. as just use fresh water inlet from spigot. if use drain that water tank. and always take water hose off and empty. I do that to ours every winter, since it sits in driveway, I leave power to it with a portable electric heater in middle of living room, when i'm tinkering outside, sorta fun to jump in warm up and sip some Java
. But when I'm totally done I don't leave the electric turned on to camper. safety reasons lolo. One thing is always keep the propane tanks full. propane don't deteriorate. Comes in handy if storm ( Blizzard) or ice knocks out power since house is total electric, at least stay cozy in Travel Trailer. I keep the Boat batterys off boat in shed in winter and keep them charged, may need to use on camper for the 12v Heater Fan.. Older model campers didn't have the fan to rely on having heat. was a good feature . but now with floor heat ducts , A/C roof ducts. about all have the 12v Blowers. I have a HD Portable Gen set, but it don't have 30 plug fro camper use
. But a v twin 16HP it loves the Gas, so will just be the 110v hook up if ever comes the time absolutely have to. But town and gas stations shut down when extreme Blizzards or ICE and no power to anyone. defeats prolonged Gen Set Runs, well have fun! about covered it all