After winterizing, replace everything and turn all faucets off. If you are using "Pink Stuff" to winterize the lines, then you want to keep your water heater in by-pass mode until the lines are flushed of the pink-stuff in the Spring.
By replacing all low point caps, flipping the on-board pump back to normal use and turning everything off, come Spring, you won't have anything lost, you know everything is ready to pressurize again, and you won't have any risk of any unwanted "things" crawling into any of the lines (outside the camper, or inside). Keeping the low points closes helps seal the lines a little better. Why leave the inside of your lines potentially exposed to (well ... anything).
If you have a thermal insulated water jug of any kind, when you store it in your garage, or closet in the house, do you leave the lid off, or keep the lid on? More than likely you keep the lid on in storage, and just rinse it when you use it the next time. Why keep the lid on? To keep it from getting dirty, and to keep spiders and critters from nest in it, and to keep from loosing the lid ... right? Same is true for the water system in your camper! Shut everything off, replace everything.
