Hi Fodorites, I'm back to solicit more ideas for my France trip! Thanks to the advice early on (merci), I have chosen Paris and Colmar as our main bases. We have round trip tickets booked to Paris (arrive 1 December and depart 14 December).
Booked itinerary so far: (Nights booked in rooms are indicated)
1 Dec through 6 Dec Paris - I may ask separately about Paris later, but have lots of ideas.
7 Dec. ??
8 Dec through 10 December Colmar - Christmas markets of course, with a day trip to Strasbourg and perhaps other villages.
11 - 13 Dec. ?? Would need to be near Paris or CDG in time to fly out afternoon of 14 Dec.
Due to early darkness and iffy weather we have elected not to rent a car, and we love taking trains. We'll probably just add 7 Dec to Paris for less moving, unless another brilliant plan comes to mind. So realistically that gives me the 11 and 12 to play with. Would you think Loire valley feasible using trains/buses? (Some have said Loire valley not good in winter, others have said the lights make some chateaux lovely.)
Mont St. Michel looks amazing but logistics - ??
Would Normandy be ridiculous? (My dad went ashore with his unit 3 days after D-day)
Would you just add a day or so to Paris or - ???
We are fairly healthy walkers but not hikers. We may not ever get back to France....such a sad thought...

I may be repeating my original question a bit, but thought I should ask again with more details nailed down. Thanks so much!

Nancy, Troyes, Dijon, Reims. I would certainly not go to Mont St Michel that time of year. It is impossible to spend too many days in Paris. We've visited Paris twice at Christmas - MAGIC.

Stu Dudley

Well, I'd pop over to Freiburg, for one thing, even if it's only for a huge bowl of Ochsenschwansuppe for lunch. And yes to Nancy, Dijon, and Troyes. I'm very much in the minority I suppose, having zero interest in Champagne or the towns that make it, so you wouldn't find me there except to visit the cathedrals.

Le Mont-St-Michel at that time of year? Not unless I was filming a black-and-white documentary about bleak, cold, wet venues. Same with Normandy. Smart people LEAVE this part of France at that time of year once they've had the requisite apple tart.

The Loire Valley is pretty dull IMO even when the weather is gorgeous. I'd feel imprisoned in bad scenery in the middle of winter as people in the Middle Ages did and lived to write about it. The smart ones saddled up and got out of town and went to war.

You can't possibly go wrong with spending more days in Paris.

Another vote for Nancy and Dijon. If you like Art Nouveau prioritize Nancy.

For me there are unlimited possibilities in Paris itself but if you want to get out you have Versailles obviously, Fontainbleau, Chantilly, Rouen, Reims. Loire Valley is possible only if you stay around like in Tours, but if you're thinking of a one day trip the only destination would be Blois, and for me it's the most beautiful and elaborate of the chateaux I visited (which I visited 2 years ago also in December. Very cold and rainy and even heavy snow in Strasbourg).

I cannot recommend this from personal experience but it's at the top of my list for next visit. I want to stay in Senlis for several nights & walk to Chantilly. For just a night or 2 I'd stay in Chantilly, you'll be close enough for a taxi to CDG.

Regarding Mont-St-Michel in winter, my visit was in March. We went to mass in the church in the evening & while there a storm broke over us. The wind howled, we were greeted warmly, the only English speakers, everything was translated for us by a woman standing a step below the alter, an altogether memorable & intensely atmospheric experience. If you really want to go I wouldn't preclude it because of time of year but you can never count on the arrival of a friendly storm. It may just be dull & I'd opt for Chantilly.

Go to Metz. 90 minutes from Paris by TGV and brilliant in December.

I loved going to Verdun. Great center for WWI history, as the battle there took over a year and cost so many lives. Fort Douaumont, the Ossuary, trenches, a unique chateau visit in the center of town, and a park with memorials.

Yes, that is a fascinaing area, but the since OP stated that they didn't want to rent a car, they couldn't see the sites around Verdun, particularly in December.

Dijon, my new favourite place.

Aw, kerouac, visiting the Verdun sites in December is certainly possible. Not only does the tourism office offer organized tours, but they can also hook you up with your own guide.

May I point out that the forts of Douaumont and Vaux are closed for the winter in mid-December? Obviously, the ossuary at Douaumont is open every day and the incredible cemetery 24/7

For anybody going to Verdun, I very much recommend the renovated museum.

Mémorial de Verdun / WW1 museum of the battle of Verdun | Any Port in a Storm

You may point that out, but the OP is not going in mid-December, the trip is scheduled for early December and all the Verdun sites are open the entire time of the trip.* I believe they close December 15.**

If Alsace is dry you could catch an early bus up to the top of the Vosges and then walk down through the forest on the top and the vinyards further down. There are lots of paths and just about every hotel will have a book of local walks.