Hey Ralftschu,
I wondered about a Harbor Master set too. At first I was like, yea, ok, but how often do adventurers deal with the Harbor Master unless you have a campaign were there was a lot of trade going on, etc.
Then I listened to Paul Senior on the World Works Radio shows and he gave some ideas, but to me it was not enough.
Then I saw the building. The first thing that went through my mind (as far as the exterior) was a great hideout for a modern setting. Even though it is designed for Himmelviel, I'll be putting it in my Mayhem setup as a bad guy hideout. It really looks like a good Two-Face hideaway, etc.
Think outside the box with a lot of the WWG stuff and you'll be able to picture all sorts of cool sh... errrr stuff to come up with.
I purchased Gothic Realms last week at first just for the sewers, then I got to looking at the walls. OMG!!!
there be skulls on the walls and the ornamentals... those would be so cool as the interior to the Hollywood flat where some EVIL GENIOUS has taken over the building and warped the internals to his own nefarious personality.... muhahahahahah.,.. cough, cough.... 
See, just because it says FORD (aka POS) on the outside, doesn't mean it can look, feel, ride like a Mercedes on the inside.
Hope this helps you see other uses for the Harbor Master set (or any other set that you might not have thought of picking up, but now can see in a new light).
CCotD' (Cerebral Cortex of the Damned enjoys the sweet of his mind)