If it helps with day trip suggestions my Dad is staying in the 19th arrondissement.

you would really have a good time in Fontainbleu. We took the train and checked out the chateau, the market and the town which was very christmasy (is that a word) and it was a great half day trip. It would be very enjoyable.

You can see what my Dad is actually doing during his trip:

http://www.fodors.com/forums/threads...p;tid=34547346

Connie