I feel silly for asking for help so early, but I can't find the Sword Key (or whatever key is required to gain access to the balcony where you use the whistle). Where is it?
get the arrow in the golden hallway that has the mirror. Examine the arrow and remove the arrowhead. Then go to the graveyard located at the landing between floors in the main hallway. Run to the back of the graveyard and examine the grave. There will be a place for an arrow head. Put the arrowhead there and run down the staircase that opens up. Grab the book on the pedestal and examine it to find the sword key
Gamefaqs.com has some great walkthroughs in case you get stuck further down the line.