reaching krabappel apartment from police station

There's an awesome step by step guide at this link ... It was the thing I used most in this whole game.

Also be sure to look at the pinned thread in the FAQ section of the forum ... The thread is called "guides and FAQs" I think.

But here's the place to find exactly who to keep free and which weird tasks trigger quest lines:

Levels 1 to 39, Krustyland, Squidport