110 miles on December 23rd - any chances?

be prepared to fix mechanicals (puncture repair obviously, chainbreaker and spare quicklink, 5 mm allen key and some cable ties are easily portable and can fix most things) because if you break down you don't want to be stuck miles from home in potentially freezing weather with a long, cold walk ahead of you.

definitely take food, and if you have one, a small thermos with hot drink in would be a good idea.
take a mobile and a bank / credit card and a map.

This and make sure your girlfriend and her folks know your route just in case...