Winter Travel - Black Forest, Bohemian Forest or Bavarian Forest

You could go north to the Sudetes, which is a forested mountain range on the northern border between Poland, Czechia, and Germany (about 2 hours North-East of Prague) This is off the beaten path, as far as international tourists go (you will mostly find Poles, Czechs, and Germans here).

A bit of context: The Sudeten Mountains (as they are known in Germany/Anglophone countries) have been at the center of a constant tug-of-war since the middle ages, between the Germans, the Poles, the Czechs, and the Austrians. The Sudetes were mostly spared from the horrors of WW2, as most of the fighting went north. So many of the historical sites are well preserved.

For potential sites you could try:

Zamek Książ - (Schloss Fürstenstein) a large, originally medieval castle of the Duchy of Pless, and overlooks the Pełcznica river gorge. During WW2 the Germans built underground tunnels here. In these tunnels is apparently where the train filled with Nazi gold is hidden. This tunnel network was part of Project Riese, which was a secret Nazi project consisting of several underground megastructures (for yet unknown reasons).

Kłodzko - which has been referred to as “Little Prague”, definitely the architecture of the town reflected that. By far the most interesting site in the town is the old Prussian Fortress that dominates the center of the town. It was apparently one of the largest star fortifications in the Prussian Empire and is in remarkably well preserved. This was in September so I was literally the only one in the fortress, had the whole thing to myself to explore!

Stołowe Mountains National Park - a primeval forest dotted with some very unique rock formations (they actually filmed one of the Narnia movies there). There are some pretty good hiking spots here.

Protestant Churches of Peace in Jawor and Świdnica - UNESCO world heritage sites, the biggest timber-framed religious buildings in Europe built after the 30 Years War when this area was part of Protestant Kingdom of Prussia.

Hopefully this gives you some ideas :)

This sounds wonderful! I'll look into traveling in this area. Thank you very much!

No problem! :)

In late December you are already into ski season and places to stay that are open around the ski hills will be pretty full. The Bavarian Forest is different from the Black Forest. Overall less traveled and not many tourists outside of Germany. Towns like Bodenmais with the glass outlets, small surrounding breweries and tourist catering hotels and shops may be worth a look/stay. Christmas decorations too late December. With only a week you would really be dedicating yourself to a day/night not frequented by most (US) tourists. I assume you will have a car? This area gets snow, so late December in the higher regions may have some (cross country skiing, snow shoeing, sled riding) and manmade on the slopes. Lager towns on the outlying areas are Deggendorf and Straubing. I would recommend contacting the tourist office in Bodenmais.
https://www.bodenmais.de/aktuelles/neues-aus-bodenmais/geschrieben/detail/neue-tourist-information-eroeffnet.html

The Sudeten Mountains (as they are known in Germany/Anglophone
countries) have been at the center of a constant tug-of-war since the
middle ages, between the Germans, the Poles, the Czechs, and the
Austrians.

They weren't the "the center of a constant tug-of-war". The only turbulent time for the Sudetes was the 20th century, when the inhabitants were expelled. That's also the reason why I wouldn't recommend the region to a tourist NOT interested in the 20th century. The population exchange meant that the local culture was lost, and the new inhabitants didn't care about a culture that wanted to kill them shortly before. As a result most of the cultural heritage epsecially on the Polish side is in a very bad shape, or already lost. On the Czech side it looks somewhat better, although the local culture was lost too of course.

Of all the four mountains ranges I would therefore recommend the Black Forest, simply because the region offers everything you were asking for, including a interesting local culture. The Bavarian Forest isn't as densely populated and offers less sights, and the Bohemian Forest suffers from the same fate as the Sudetes: the locals were expelled, and the local culture was lost (and the repopulation was only partly successful, and many villages died out and are gone now).

If you can fly out of Berlin you could also consider Saxon/Bohemian Switzerland, 90min to the north of Prague. That's something completely different, as winter sport isn't possible there, but if it isn't slippery it's a great area for hiking. And in the surroundings are castles, fortresses, cute little towns and Dresden, which offers many world-class museums.

I would observe that the Black Forest is quite beautiful, but it is not short on "tourism infrastructure!" And I would think that prompt and reliable snow-plowing is important to your trip. You weren't planning to snare squirrels and build a fire to feed six people! As others noted, this clearly needs a car, and big one. Can you drive a standard shift if necessary? Don't forget about drop off charges to return in another country.

Here are two old threads that might also give you some ideas:

https://community.ricksteves.com/travel-forum/czech/after-prague-eastern-czech-republic-or-eastern-germany

https://community.ricksteves.com/travel-forum/czech/the-rhetoric-of-war-and-remembrance-focused-on-wwii-and-the-cold-war

Both recent responses are super helpful and interesting. Thank you very much for that information!

They weren't the "the center of a constant tug-of-war". The only turbulent time for the Sudetes was the 20th century

Contrary to your "version" of events, during the early to late middle ages this area was in fact part of the Piast Kingdom of Poland. Known as the Duchy of Silesia it was ruled by Silesian Piasts. It then was transferred to the Bohemians (Czechs) in the 1335 Treaty of Trentschin, but continued to be ruled by the local Silesian Piast Dukes. In 1476 it became part of the Margraviate of Brandenburg, when the widow of the Piast ruler, Barbara von Brandenburg, inherited it. In 1526 the region was acquired by Austria's Habsburg Monarchy after the death of King Louis II of Bohemia. Brandenburg contested the inheritance, citing a treaty made with Frederick II of Legnica, but Silesia as a whole largely remained under Habsburg control until 1742. Most of Lower Silesia (including the Sudetes), except for southern part of the Duchy of Nysa, became part of the Kingdom of Prussia in 1742 after the First Silesian War. In 1806 confederates of Napoleon invaded Lower Silesia. In 1813 this part of Silesia (Kłodzko in particular) became the center of a revolt against Napoleon.

There was still a major community of local Polish and Czech Silesians when this part of Lower Silesia was part of the Prussian/German Empire. (Many of the "German" palaces and towns in the area were actually built on top of originally Polish medieval castles and villages.)

The population exchange meant that the local culture was lost, and the new inhabitants didn't care about a culture that wanted to kill them shortly before.

Can't tell if you are actually serious here or if this is some kind of joke. The Poles and Czechs WERE a significant part of the population of the area pre-WWII until a little something called National Socialism came along and started to enacting laws banning Polish and Czech from being spoken in public. During WWII around 50,000 Ethnic Poles were forcibly removed from the area and replaced with German settlers from Eastern Galicia and Volhynia. 23 camps called Polenlager were established across Silesia (including the the Sudetes) for these expelled Poles.

As a result most of the cultural heritage especially on the Polish side is in a very bad shape.

This was already happening when this was part of Germany in the 1930s. Many of the historical sites were neglected by the German owners and a lack of state funding from the central government in Berlin meant that the historical sites were falling into disrepair. In fact, it was thanks to the Polish government post-WWII that these sites were saved and preserved. In recent years, for example, large parts of the interior of Książ Castle (German: Schloss Fürstenstein) have been elaborately (and painstakingly) restored. Another example, the Protestant Churches of Peace in Jawor and Świdnica were both restored by a Polish–German historical group, and recognized by UNESCO as a World Heritage Site in 2001.

This is directly from the UNESCO website:
"Renovation and conservation work (including preventive conservation measures) carried out on the churches has preserved their Outstanding Universal Value and authenticity by slowing down the processes of deterioration. A full programme of conservation is applied solely to individual elements of the décor and furnishings. The only new technological elements introduced in both buildings are alarm and fire prevention systems. There are no potential threats and risks identified for the property."
https://whc.unesco.org/en/list/1054

If you stay in southern Germany, which I'd recommend, look around for a local spa/waterpark. these are NOT like what you may be used to in the USA. Think more like a place where the kids can swim and surf in pools with waves while the grownups sit outside in hot tubs with full bar service and then enjoy a sauna or tan. You can get the full spa treatment or just lay around with booze and food. It's a really nice break from the cold outside.

Here's a link to the one in Nuremberg I used to visit: http://www.palm-beach.de/

Other towns have them, including Baden and Munich. In Garmisch the old Olympic pools are open to the public with an attached spa.

Germans get "health" days to take advantage of these types of spas paid for by health insurance.

I've spent a lot of time in the Black Forest and like it.

I also stayed in Zwiesel, in the Bavarian Forest, for three nights. There are several nature preserves in the Bavarian Forest, but the animals they actually had to see were pretty mundane. In the few weeks after I came back, one day there was a mountain lion in a tree in a neighboring town (Morrison), and then we went up to Estes Park and saw wild Elk lying around on one of the greens on the town golf course. I said, "I don't need to go to Europe to see wildlife, I live in a "preserve".