The Key, or as your trying to say Rockhopper's Key Pin is located in the room above the coffee shop. The room above the coffee shop, which is called the Book Room. In the book room is a bookcase click on it, and there will be a book about Rockhopper, flip to the end to get the key!
you find it at the dance club
key
The Hidden Lake
You can buy a club penguin guide book. Then, look in the content for key merchandise and go to the page.
nothing
under the lounge
in the hidden lake
noting
with a key!
in the library
it is in the mansion
blv