Recommend big towns/small cities for my active family?

It's on the Neckar but otherwise Tuebingen might work for you

Of your list I've only been to Quedlinburg, Dresden and Schwerin. I cannot speak to outdoor activities beyond walking around the cities themselves because I was hobbling around on two sprained ankles during my time in Germany, but here are a few comments:

Quedlinburg: drop-dead gorgeous and with a very large historic area. Castle in town. Cathedral with impressive treasure linked to the U.S. (Google for info.) Small modern-art museum. I believe the tourist ofice runs occasional English walking tours. If the timing is not convenient, I can recommend the audio guide the T.O. rents out; it will take hours even if you see the castle and church separately--there's that much ground to cover. A very popular place with European tourists, but you'll encounter few Americans

Shwerin: It is indeed rather far north, which was a plus for me since during my summer 2015 trip it was the only place other than tne Dolomites where I found cool (and rainy) weather until well into September. Very pretty historic area much smaller than Quedlinburg's. Castle with surrounding garden in tiny artificial lake. It felt like there was less to see there than in Quedlinburg, and the castle may not be what traditionalists are expecting, but I did like Schwerin. However, geographically, to go all that way north and not see Lubeck or one of the other Hanseatic cities... That's what I did due to time pressure, and I regret it.

Dresden: Home to some large, classic museums. The Historic Green Vault (get your timed tickets immediately upon arrival if you opt not to book them in advance) has the single most impressive collection of precious objects I have ever seen. I'm sure it is just too much for some folks, but I really enjoyed it. The regular Green Vault isn't chump change, either. Other museums or wings thereof have art, porcelain, armor, etc. Central Dresden was fire-bombed into oblivion during the war. Only a small part of that area was rebuilt (very handsomely) in the historic style. The T.O. offers a walking tour that provides some historical background (that I needed) on earlier periods.

Allow me to mention one other city that, aside from being very worthwhile itself, offers a couple of really good day-trips. That would be Erfurt. It came through the war unscathed and has a pretty historic district that includes a merchants' bridge and two cathedrals. It's a university town with the lively streets you find in such places. There's a Luther connection and possibly related stuff to see locally; I didn't research that. Excellent side-trips to Eisenach, also a pretty place, and with the really impressive Wartburg Castle, where Luther stayed; and to the historically important Weimar. The Buchenwald camp is on the outskirts of Weimar. It was re-used to house enemies of the GDR after the war, so there are two layers of history to explore there.

We are considering: Nuremberg, Dresden/Meissen/Bautzen, Quedlinberg,
Michelstadt/Miltenberg, Marburg, Schwerin (far north but looks
amazing!), Goslar, Bamberg.

I think in terms of active holidays Dresden, or better the Elbe valley, is the best option. Down the river are the vineyards of Meissen and Radebeul, up the river are the Elbe Sandstone Mountains/Saxon Switzerland (with hikes like THIS (rotate!)). Both are connected by train, the biggest paddle steamer fleet in the world, and Germanys most popular cycling route, the Elbe Cycle Route, with several castles along the way. You can also rent a rubber dinghy and drift down the river.

As already mentioned, the centre of Dresden was completely leveled, and only a small part was reconstructed, so the centre is obviously not what you are looking for. On the other side of the river is the mostly preserved Neustadt (new town), a lively 19th century quarter, but that's not what you are looking for either. I think you would like the suburbs of Loschwitz and Wachwitz around the Blue Wonder Bridge, former wine villages which were turned into very posh villa quarters... once the most expensive residential quarter in Europe.

A good option would be the small town of Pirna, halfway between Dresden and Saxon Switzerland, which offers a cozy, preserved old town on the banks of the Elbe river. From there you can take the train or paddle steamer to Dresden or the mountains, or cycle up and down the river (and return by train), or take the train to the Czech/German border and a rubber dinghy back tor Pirna and so on.

Thanks so much for the helpful feedback! I'll research the options you suggest.

Thanks so much for the helpful feedback! I'll research the options you suggest.

Hi,

From your list indicating the type of places that appeals to you, I have been to Nürnberg, Dresden, Meissen, Marburg an der Lahn, and Schwerin.

Schwerin is the one I saw the least due to lack of time but the small places Marburg and Meissen are well worth your time, have been to both places at least twice or more. Of the small places listed, I vote esp for Goslar....still haven't made it there yet.