Northern Germany in March, 2025

Not quite sure what your question is?

I find concrete questions easier to answer.

Re: a small town in North Germany, which one?

Lots of them worthy of your time and energy. How far north? Lower Saxony, Schleswig-Holstein, or even eastward into Brandenburg?

I have numerous places in North Germany to suggest, depending on your specific interests. How much time are you devoting to spending in North Germany? It seems from above it's about 3 full weeks.....good.

If you include towns on the Jutland peninsula, ie Schleswig-Holstein from the Baltic to the North Sea, lots of places worth going to, historically and culturally, totally off the tourist radar, except that of German tourists, if even that. That you will see when using public transport where all the other passengers are locals.

Sometimes places on Jutland can feel a little strange ... (photo). And yes, also worth exploring.

If you're after architecture that escaped the ravages of war in 1945, Schleswig-Holstein has such towns. Flensburg , Schleswig, Eutin/Holstein, Lauenburg an der Elbe are a few of them. Further south also Lüneburg.

Don't forget Kiel , maybe not so its Zentrum which was among the first cities plastered by the British in early 1942 but the Kiel harbour. tour, which goes from Kiel dep. point ca. 30 mins or so from the central station to Laboe, before turning around, the site of the naval war memorial and museum (Marine-Ehrenmal) if you're interested in that regarding history sites.

I use only public transport in North Germany too, the primary junction point is Hamburg Hbf and ca. 2hrs south the other lesser one is Hannover Hbf. Taking the regional trains and the S-Bahn (depending on the destination) will get you towards the North Sea, Cuxhaven and unique little towns such as Husum and Heide.

Bottom line here on your final choices in North Germany: Absolutely no need to be concerned with having to deal with tedious crowds, these unique places are not swamped and teeming with tourists, not even in high season, ie, in the summer when I visit them, let alone your projected time period in March/April.

Just be warned that Germany in the early spring is usually cold and rainy especially in the North-pack accordingly.

Wunstorf / Steinhuder Meer . In my opinion a very nice small area in Germany. End March it could be cold, wet and grey.
near Hannover

Lüneburg might be an option to do a city tour

Good direct train connection from Hamburg ca 30 min from Hannover ca 1hr