I'm down in Olympia, swamp, and I leave all my Sarrs out year-round. Almost all of them love it - certain ones like alata and leucophylla hybrids continue making new growth clear up to the frost. I would suggest sheltering the more southern species like minor, and in the late winter/early spring moving them into a spot like a warmhouse or coldframe where they can get a little early season warmth. Otherwise they get cranky with our long cool season. But the bulk of the Sarrs I grow genuinely seem to love the climate here. When it snows, let the snow pile up on the pots and it'll be plenty of insulation.
The big danger in winter are clear, windy days when it gets cold and dry. Repeated freezing and thawing will basically give your plants freezerburn; the crystallizing water expands in the plants' cells and is drawn out. Cold air also holds much less water than warm air, so wind in the cold evaporates and disperses water much faster than at warm temperatures - even frozen water.
If your pots become frozen, do not attempt to thaw them. Your plants can take care of themselves at below-freezing temperatures. Just let them warm back up naturally as the weather improves. Keep your pots gathered closely together so that the sides are insulated from the cold air and warming by the sun. Make sure that they have water/ice around the bottom of the pots, but you don't need as high a water line as during the growing season, since they won't be using much water. Do watch for evaporation, though. (And if you keep VFTs, note that they really don't like having their roots submerged during our winters - make sure to keep them in a very shallow tray, or no tray at all if you can check daily to make sure the soil isn't drying.) If your yard is naturally windy, you can move your plants up against a building, wall or hedge to protect them from the wind. They won't notice a little more shade this time of year. I do believe that direct midday sun is still beneficial in this area, though - especially as close to the open (well, somewhat open) water as Olalla is, the freezes won't be constant or deep enough for the plants to get really sleepy and stop photosynthesizing entirely.
As for pruning, you can more or less do what you like. Don't trim pitchers that aren't beginning to brown unless they're really torn up or so ugly you really genuinely can't stand it. Wasps chew holes in my pitchers, and they get squished sometimes, and just otherwise beat up in general, but I leave them on if they look green. Certain plants hold on to their leaves longer - purpurea and hybrids for up to two years I think - but in addition, different species drop their leaves at different rates. S. oreophila seems to gradually lighten from bold to yellowish green at the end of the summer, and then once it gets wet and cold the pitchers all just suddenly go red/brown and fall over dead in the first windstorm. Other plants let their pitchers die halfway down and then manage to keep the rest of the leaf green halfway through winter. It's mostly a matter of preference how you trim - eventually they'll start decomposing and fall off on their own, and likewise a leaf that's already fading won't be missed if you clip it a little early.
I tend to wait until most of my plants have dropped a substantial amount of pitchers, then I go over my whole outdoor collection and remove fallen leaves, tree seeds, dead pitchers, weeds, etc. I try to clip any brown stuff that has died enough that it's spongy and absorbs rainwater. But I leave stuff that's still crisp and not too yellowed - some plants get a blotchy sunburned look in the cold, and are much more red than in active growth, but I think those leaves can still photosynthesize. After that I usually try to do divisions and repotting, but sometimes I'll leave that part until the end of winter instead. But the pots have to be trimmed and cleaned at the end of the grow season to keep things from getting unmanageable - live Sphagnum colonies in some of my pots also need to be trimmed at this time to avoid them spilling into other pots or smothering small plants. (I trim the biggest colonies once near the onset of the rain, once shortly before the summer heat, and sometimes once at the end of winter as well.)
~Joe