Visiting U-boats at Germany

I'm planning on visiting the U-995 at Laboe as well as Wilhelm Bauer at Bremerhaven. The time of the trip will be early July this year.
I'm planning on flying to Hamburg (from Finland) and staying there for three to four nights. From there I'll be renting a car and driving to these locations so that I reserve one day per sight.

Any tips for me on this journey? Any other good sights/museums in the vicinity of Hamburg (maybe 2h driving distance max from Hamburg)?
I already saw that there's a tank museum at Munster which I'm going to check out.
Also it seems there are some submarinen pens at Bremen which I'll surely visit on the way.