In reply to my good friend RBDodger...don't hate the pretty...I do skin down to almost nothing. the good Lord blessed me with extra gut ... that emits it's own heat. Last weekend it was down to 10* and I had to take off everything but my long john bottoms, and then I vented in the middle of the night. I typically put my clothes in the bottom of my long bag, in case I do get chilly or need the 3:00 am coffee release.
RB on the other hand looks like Nanook of the North when he climbs in the rack, he has a hood and mittens and down booties.
So I say try it. Try changing clothes, and not changing clothes. I train my boy scouts to change clothes before bed especially in winter, because they romp in the snow and get wet...and wet is bad. But for grown folks, I think between me and my best trail buddy you have two ends of the spectrum...you are probably gonna be somewhere in the middle.
See you on the trail.