We are planning a family trip to Germany this summer for the 500th anniversary of the Reformation. I have two sons (10 and 8); the older one loves museums and history and will be fine, but the younger one prefers being outdoors, nature, hiking, etc., and wishes we were going to Yellowstone instead. Does anyone have suggestions for activities that he might enjoy in Germany? We will definitely be in Wittenberg and Eisenach, and we will probably fly in and out of Berlin. Other than that, our itinerary is flexible - we are considering time in Munich/Bavaria, and possibly another "big" stop like Vienna or Prague. Also, we will not be renting a car on our trip, so any activities/sights need to be accessible by public transportation. Thanks for your suggestions!
Between Wittenberg and Eisenach, check out the Harz mountain region. The towns are very well preserved, but for the younger son, he may enjoy hiking to the summit of the highest mountain, Brocken. The hike is fairly easy, and the summit has an observatory, hotel, restaurant and beer garden. Without a car, your easiest option would be to stay in Wernigerode, take the steam train up to the village of Shierke and hike from there. A reasonably fit individual can do this hike in about two hours. For those with lesser mobility, the train continues to the summit.
The Alps south of Munich offer plenty of outdoor hiking options. There's more than enough moderately challenging hikes around Garmisch-Partenkrichen. The town also has a Kletterwald (like a rope course), and I'm pretty sure they also have a Sommerrodelbahn (luge, or mountain coaster). Both of these activities are fairly common throughout Germany, so keep a look out for brochures.
You're not going to be that far from the Naturpark Duebener Heide (Nature Park Dueben Heath). They have a really nice website geared to exploring and hiking in the surroundings. www.duebener-heide.de. Bad Dueben itself is very nice. (Pack swim suits, you'll find public pools.) Also, check out the Woerlitzer Park (on my agenda for this year). www.woerlitz-information.de. If there are no train connections, there will likely be a bus. Also, you can take a boat tour on the Elbe river at Wittenberg. Do any of you speak German? That would definitely help with the research, I didn't see a good website in English but I speak German. I may just visit Wittenberg, too. Have never been there and it looks great for a day trip.
RE: Wörlitzer Park (AKA, the Garden Realm of Dessau-Wörlitz). An 8 year old might find it interesting, or conversely, may be bored to tears, depending on the individual. In the middle of a museum-heavy European trip, I would have loved being set loose here at age 8. There's a lot of little whimsical nooks and crannies, like tunnels, artificial caves, classical Greek-style pavillions, etc. So, since you know your kid best, you can decide if it warrants a look. For your trip, it has the advantage of being very close to Wittenberg.
I have always thought Saxon Switzerland National Park, which is near Dresden, looks really great. It is listed in Rick's 2006 book, and you can go to Google images and check it out. It looks like a place where you could spend days. If you make it to Neuschwanstein, there is a trail that leads up a steep hill for a fantastic view of the palace. The guidebook shows quite a few other trails and a gondola around there too.