This December my husband & I are considering taking the family to Germany (2 girls in 20's with spouses & 1 boy in 20's). We want to spend time visiting different Christmas markets but sightseeing is also important. I am only in the beginning phases of this & am looking for some ideas of best routes to look at. We're looking at 2 weeks (14 nights) & have the kids join us for the 7-8 nights at the end. I'm thinking it would make sense for the kids portion to be in larger towns where there is more to see & do as we will likely break into groups during the day depending on interests & meet up at the Christmas markets late afternoon, early evening. My husband & the boys have never been to Germany but the rest of us have been in Salzburg, Munich, Fussen & Rothenburg OBT. I've been going through older posts about the Christmas markets & so far some of the markets I seem to find most interesting include: Nuremburg, Regensburg, Lindau, Colmar, Strasbourg, Salzburg, Budingen, Idstein, Berlin, Dresden. Driving is fine when it's my husband & I, but when everyone else is here I think it would make sense to stay in places where day trips are easy by rail. I am good with an open jaw ticket. If anyone has some suggestions on itineraries, I would love your input.
I've seen a good number of Christmas markets, the Nuremberg market maybe the most memorable, but Christmas markets are nearly everywhere these days, and to a certain extent, a Christmas market is a Christmas market, and they're almost all enjoyable in some way, so I think I would zero in on your group's common interests as the basis for your itinerary rather than on the comments you may get about this market or that market being wonderful. Unless you plan on winter sports, most of your activities, aside from the markets, will likely be indoors - museums. galleries, churches, castles, cafes, and beer halls, I imagine. So is your group into art? History? Architecture? Cars? If your "open jaws" flight means FRA at one end, Frankfurt might be a good base and a good place for indoor stuff - lots of museums there. It's a good base for trips to Idstein and Büdingen, and I'd also consider a daytrip to Mainz, or possibly using Mainz as a base for daytrips by train along the Rhine - Braubach's Marksburg Castle is open all year round for tours and can be reached from either Mainz or Frankfurt by train via the scenic Rhine Valley; Mainz, Speyer (a rare town where the Christmas market extends into the new year) and Worms also have great Romanesque Doms. A Mainz base would allow you to use the Rheinland Pfalz ticket (daypass) for all these destinations - details are HERE.
I have been to the markets the last two years and if you would like to see my blogs for my trips, send me a personal message for the websites. You can see how my itineraries worked out. As far as cities with things to see and do during the day, it depends on what your family enjoys seeing and doingmuseums, cathedrals, castles, hiking? Like you noted, maybe fly into Frankfurt and out of Munich or Salzburg.