SG, Good for you. As you said, now you know why so many of us recommend trying gear out before the big trip.

As far as getting cold-try eating more right before bed, so your body has some fuel in it. Chocolate or something similar is a good bet. That plus a hot drink should help. You will be burning more calories than you think, so don't worry about over eating. Fairly unlikely.
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Don't get me started, you know how I get.