West Wing
Once you are inside the castle's hallway, have one of the masks listed above on. This causes the Re-Deads to dance. Now go and kill the re-deads with your sword. You will then get an easy 15-20 rupees. Now look for frozen eye switches on pillars. Melt them with the fire arrows. Now the bars will open to two doors. Go through the one one the west side. You will be working through the West Wing now.
In the first room, a crystal switch controls the red hot floor. You cannot walk on it because it is simply too hot. Shoot the switch, and turn into deku Link. Run as far as you can and dive into the deku flowers there. The floor will fall but you will not be hurt. Just jump out of the flower and the floor will rise back to the top. Of course, the height of your jump will be affected. You want to jump to the column near the end with a switch. As normal Link, step on it, and the door opens. Now if the floor falls back down, you may think you are stuck. Just shoot the crystal switch on the other side and you can now finish the room.
In this next room, your Lens of Truth will come in handy, along with your bow, so be sure to have arrows. Now, as Deku Link, use the Deku Flower to shoot over to the switch. Step on it as normal Link, and the door opens. Now use your bow to shoot down the Giant Skutulas to make your jumps to the door safer. Now jump over to the door and go through it.
Run past the blue bubbles in the next room. You can defeat them if you want. If you get cursed, use the Song of Storms. Now, you will notice a piece of heart to your right. Before attemting to do that, you need to trigger a switch so you can set up things on the East Wing. Climb on top of the balcony, and walk across the thin edge to the front of the castle. Jump onto the awning and use the Deku Flower there to launch to the switch that floods the East Wing. Now you can go get that piece of heart that you saw when you entered. Use the Deku Flower there to get to the opposite pillar and get the piece of heart. Just shoot the pillar and the fire goes out. Now use the deku flowers there quickly to get the piece of heart. Now head back to the entrance of the castle, and head through the eastern door.
East Wing
The East Wing is very similar to the West Wing in that you have to go through a series of rooms to get to the balcony area. It is also filled with re-deads, so you have a perfect chance to fill up on money if you have the gidbo mask.
In the first room, you have to defeat the floormaster. These monsters are completely opposite of their cousins, wallmasters. They rely on brute strength, instead of surprise. To defeat the floormaster, just slash it with your sword. Then it turns into three smaller versions. Quickly dispatch them before they grow into three bigger floormasters. Watch out when it turns green. That means that it is going to do its body slam attack. Run away when it does this. Once you defeat it, use the mirror shield to reflect sunlight onto the sun block, and make your way into the re-dead passage. Defeat the re-deads in that passage and head through the door.
In this next room, you face an oh so familiar face; the Wizrobe. This time, he is shooting lava instead of ice. Defeat him the exact same way, and watch out for the lava. Now after you defeat him, head through the door and kill the re-deads. Head up the stairs to the hallway. Now you are on the balcony. Walk around to the front of the castle. You will then see a big crack. If you miss it, Tatl will point it out for you. Now put your powder keg on that crack. When it blows up. Jump down back into the entrance. Then you will see a sun block. Reflect the sunlight onto this block, and enter this room
The Ikana King and his Servants
The Ikana King and his servants are actually quite easy to defeat. They may look really hard. When you enter, you notice that the king closes the windows with curtains. You want to open those curtains. Melt them with fire arrows. You can use this as a mini defense post. The servants are like most swordsmen. Quick to defend and quick to attack. You can defeat them by only using a certain combo. You have to stab the with your sword and reflect sunlight using your mirror shield. Once you defeat both swordsmen, the King stands up, and challenges you. Do the same as you did to the swordsmen to him. He is really just a quicker version of the servants. He also has two other attacks. A breath attack, which is pretty wimpy. And one that he takes his head off of his body. To escape this, run around and don't get caught by his head or his body!!! Once you defeat the King and his servants, you go into a cutscene. The servants start fighting with each other, as they only have their heads. Then the King comes in and tells them that a warrior great enough to save Ikana has come, and then he teaches you the Elegy of Emptiness: C-Right, C-Left, C-Right, C-Down, C-Right, C-Up, C-Left. Now, you are ready to go to Stone Tower and save Ikana!