We take a Xmas Market River Cruise every other year - we have been on Viking, AMA, Uniworld and Tauck - -- Tauck is the BEST, it's all inclusive, top shelf alcohol anytime, all tips, excursions, port charges included. The service, food and guides are 5 star. We have been on many of them and we LOVE the Danube one the best -- Vienna, Melk, Salzburg, Passau, Regensburg and Nuremberg.
The Nuremberg market is one of the oldest and largest and we LOVE that town. We always stay a few days after the cruise ends - we love Hotel Victoria.
We usually take the train to Munich and fly home from there, but the Xmas Market is Munich is very UNDERwhelming.
Feel free to PM me with questions. We are going in 2022 and 2023. If you plan to do a River Cruise, you better book ASAP - 2022 is almost full and 2023 is already booking.
If we were going to base out of towns and NOT do a cruise - I'd say Vienna, Salzburg and Nuremberg.
You can take the train to Munich as it's easy to fly home from there and there is a great day trip from Munich to Regensburg Xmas Market with Radius Tours (recommended in the RS Munich book) - it is worth it!!!