I just found this thread...and would love to start winter or shoulder season backpacking. I hope you will pardon some novice questions:
1) Years ago I took a snowcamping class in Oregon. It was fun, but I was chilled the whole time. When you wintercamping folks are in your tent, are you chilled (not dangerously so, but just uncomfortable)? I'm wondering if I just need a warmer sleeping system, or warmer clothing.
2) Do you find bivy sacks useful to help keep warm?
3) Do you worry about gloves and shoelaces freezing? Do the tents keep them warm enough?
4) I live near the northern Colorado Rockies, and one thing that happens when a cold front comes in is that, depending on conditions, topography can cause 20F variations in temperature, so a cold front that brings in 0F (-17F) to some areas can cause -30F (-34) in certain valleys. While this might happen only once or twice a year, is this something that you experienced folks think about, ending up in conditions where cold pools in a valley (not small topographic variations like being near a tarn, but over larger regions).
5) At what temperature do you decide it isn't fun? Not that I am going to go out as a novice in really cold conditions, I'm just curious.