7 day itinerary in December

I'd stay close to Munich because traveling takes lots of time. Plus there are great towns nearby with excellent markets.
For Munich, we love bighattours.com
He has a great Third Reicht Tour and tour of Dachau Concentration Camp.

Munich has three good markets very close to each other - the main one at Marienplatz, the smaller one at the Residenz, and one right around the corner which is small, but unique -- it's a medieval market - excellent food. I suggest you stay near Marienplatz. We love Hotel Platzl or Hotel Schlicker -- the hotels near the markets book out VERY fast - I'd reserve NOW.

Then do a couple days in Nuremberg - a little over an hour train ride from Munich. Lots of WW2 history here- the Nuremberg Trial Courtroom. Stay at Hotel Victoria - it is right across the street from the train station - you can even walk underground and be there. It is quaint and has a free breakfast that is very good. Check it out on TripAdvisor, but book direct with the hotel. We stay here almost every year. The Xmas Market is very close by - as are 3 spectacular cathedrals. The Nuremberg Xmas Market is one of our favorites in all of Europe - we find the food and products the most authentic.

Another great option is Salzburg - easy train trip. The town and market are excellent.

Another great option is Regensberg = the town is so cool. The main market is ok - - but if you are willing to pay, the private Thurn & Taxis Market is our favorite in all of Europe. I don't recommend seeing the palace as it's not so great, but the market surrounding it is fabulous. Be there at day and night - at night, it is super authentic from centuries ago - no lights, all fires - it is stunning. Get tickets online before you go.

Don't try to do too much - a week isn't much time at all.

We go over almost every year for at least two weeks. Please know it takes lots of time to change locations.

If you want to go to Munich, it might work best for you to go to Salzburg and Vienna. All have excellent Christmas Markets and are close enough for you to do in a 7 day itinerary. Friends of mine actually stayed for a week in Vienna and took day tours to Munich and Salzburg. Be sure bring Snow clothing. My friend sent us Facebook pictures to us which showed her in her Parka. They still had a great time at the Markets which are spectacular with all the festive lights. The Booths are usually in decorated wood sheds, but are still outside. RS actually has this in a tour, so you can look at the itinerary. Most European Countries have Christmas Markets. Another friend of mine took a River Cruise that visited Christmas Markets along the way.

Munich -- good for WWII and Christmas Markets. Website that lists 2023 Christmas Markets: https://www.munich.travel/en/topics/markets-festivals/christmas-markets

Nuremberg -- good for WWII and Christmas Markets (though the Christmas Market is absolutely PACKED on weekend evenings.

Berlin -- good for WWII (and Cold War history) and okay for Christmas markets.

I would choose Munich + Berlin over Munich + Nuremberg, but either is good.

If doing Munich + Berlin, consider a stop at Erfurt. There are many lockers at the train station for storing luggage. Erfurt has a quite gorgeous Old Town that largely escaped Allied bombing during WWII. It's Christmas market is on the spectacular Domplatz.

Little known Cold War history... Erfurt was the first East German town to host a West German Chancellor -- Willy Brandt. A large crowd of East Germans showed up to welcome, see and cheer for Brandt -- surprising Western journalists and embarrassing East German officials. The crowd cheered louder and louder, trying to get Brandt to come to a window of a hotel where he had meetings. Brandt briefly appeared in the window, gave a little wave, and then disappeared, trying to acknowledge the crowd without further embarrassing East German officials. And so... you will find Willy Brandt Platz right outside Erfurt's main train station (Hbf).

Other things of interest in Erfurt:
- Recently named a UNESCO World Heritage site for Jewish Medieval Heritage for, among other things, its medieval synagogue that escaped Nazi destruction because it had been re-purposed as a warehouse well before the Nazi ascension to power.
- Stasi Museum and Prison
- A really cool Merchant's Bridge
- Topf und Söhne museum -- museum in the building where "normal" men employed by a German conglomerate engineered the ovens of Auschwitz and other concentration camps
- Anger One -- building that formerly housed a Jewish-owned department store that was Aryanized during Nazi rule, then converted to an East German government-owned department store and is now a Karstadt department store (+ other stores).
- Martin Luther sites

Stay in Munich. Buy the Bayern Pass for the trains; it lets you use the S and U bahns, and the trams. It will also let you go to Nuremberg and Salzburg, and that's all you're going to need. Those three are great and will easily fill a week. But you can also hit a number of other smaller towns if you somehow have time.