Where to recommend in northwest Germany

You could try Aachen, which was Emperor Charlemagne's headquarters. He is buried in tte Aachen Cathedral.

Cologne, Dusseldorf, Monschau, Munster, Kassel. I think Munster may be the most historic. I'm sorry to have missed the Museum of Funerary Culture in Kassel, because that is so different in Germany than in the USA.

It is true that D'dorf is famous for its brewery restaurants ("Dusseldorf, the world's longest bar"), but they are rather old. I wanted to see the Kunstakademie Dusseldorf because it has had so much influence on WORLD contemporary art, as has the 10-year interval fairs in Kassel, Documenta. It is easy to combine a visit to Cologne and Dusseldorf. Despite war damage, Cologne has plenty of old stuff, including Roman relics (and a great Roman museum.) Of course it involves mythology, but read up on St. Ursula. Dusseldorf has a wonderful monthly FIsh Market, which is actually a beer and sausage based street fair along the river, you have to check if you're traveling the right .... Sunday (?) Saturday (?)

I have asked here if there are any traces of Anne in Kleve, but have not gotten a concrete answer!

Aachen could be a good choice. More than a millenium after Charlemagne, Aachen and the nearby Hürtgenwald (forest) became very important places to my father's generation of Americans as WW II was approaching its finale. I'm sure you know more about the Westwall battles than I do, so the place names at the page below will probably sound familiar to you. I've seen some small museums, bunkers and "dragons teeth" further south along the Westwall but not the Hürtgenwald. Seems like you should be able to find these types of sites there as well. There's a Hürtgen military cemetery with some 3,000 German graves. Many of the 30,000 Americans who died are at Henri-Chapelle American cemetery in Belgium, not far from the Hürtgen forest.

https://wargamecenter.wordpress.com/2011/11/07/visiting-battlefields-the-huertgen-forest-and-the-siegfried-line/

Fantastic that you studied modern German history as the focus. Bonn is/was exactly one of the most famous Uni in Germany re: that subject.

Looking for towns near (or relatively) the German-Dutch border dealing with history, especially Prussian-German history and also WW2: You have indeed a good number of choices, eg, Wesel am Rhein, Kleve, Dortmund-Hohensyburg, and Ratingen,...if you want esoteric modern German history.

Re: I heartily recommend based on your studies/interests, etc the 2 museums in Ratingen (Landesmuseum Oberschlesien) and Wesel (Preußen im Rheinland), covers much more that is suggested by the title.

Heinrich Heine's Museum/House is in Düsseldorf if you're into the German language and his poetry, As in Cologne, Düsseldorf has a Doc. Center on Nazi history.

On my first trip to Germany, I made it point to visit Bonn, one, to see its famous Uni and its dynastic connection and, 2. also to visit Beethoven's House/Museum.

I would suggest also going from Bonn to Bad Godesberg, see the hotel where Prime Minister Chamberlain met with Hitler in his attempt to stave off an imminent German attack for which Hitler at the moment was not operationally prepared to launch.

Xanten! Go there.