The best piece of clothing I have ever bought for winter cycling and/or camping is an Endura Baa Baa long-sleeve base-layer.
It's Merino wool and therefore warm when it's cool, cool when it's warm and doesn't smell (even after a few days).
I plan to wear wear it once we get back from the cycle ride, as a jersey, later as a pyjama top and then again in the morning.
Can't recommend it highly enough.