If you can sneak a look at and get some titles, or even the full list, of the gramaphone records they listened to, that would be great!
If you can bring a camera, detailed panoramic shots of all compartments would be nice too.
Pictures of the Radio/Sonar room. In SH3 its the same compartment for XXI, VII, and IX boats. I would have thought the IX ones would have looked different.
The conning tower, inside, as well.
Close up pictures of all the equipment. Anything in short that modders might find handy in the future.