J-man Zelda Fan's walkthrough of The Legend of Zelda: The Minish Cap
"Sidequest Silliness" (Magical Boomerang, Mysterious Walls, Remote Bombs, Light Arrows, Mirror Shield)
Quest for the Magical Boomerang
In the eastern part of South Hyrule Field, use the Cane of Pacci on the hole there to launch up to an area where you will find Tingle. Fuse Kinstones with him to create an opening in the one of the four trees in the center of North Hyrule Field.
After all four fusions have been made, travel to the trees in North Hyrule Field. Enter each tree and go down into the cave. Step on the switches to light the torches. After all four torches have been lit, a ladder will drop down in the center of the area. Go back outside and go down the ladder. Open the big blue Treasure Chest to get the Magical Boomerang!
Mysterious Walls Sidequest
First, you have to fuse with Eenie is his field to give the Goron in Lon Lon Ranch the strength to break into the cave. After that, you need to find the five Mysterious Walls in Hyrule and fuse Kinstones with them.
Mysterious Wall One
If you fuse Kinstones with Gentari, the same Minish that you originally got the Bomb Bag from will suddenly come up with the idea of Remote Bombs. Go talk him to replace regular bombs with Remote Bombs! These handy bombs can be detonated whenever you want by just pressing the button they are assigned to. (first set it down, then press the button again to detonate it). These bombs provide a good way to kill Darknuts in Dark Hyrule Castle and in the final boss fight.
This quest must be done before entering the Cloud Tops. To obtain the Light Arrows, you have to fuse Kinstones with the stranger in the house in the western part of Hyrule Town, right next to the western exit. Once you've fused with him, a strange portal, which kind of looks like a glowing egg, will appear in South Hyrule Field. Go there and step into the portal to be taken to the home of the Wind Tribe. You'll be here later in the game for the next to last dungeon. Make your way through the large mansion and enter the various rooms and open the treaure chests for Kinstone pieces. Eventually you will come to a room housing a sickly-looking man with a ghost flying around him. This man is Gregal. Use the Gust Jar to suck the ghost away. Now later, when you come back to this location before entering the Palace of Winds, talk to Gregal, who will give you the Light Arrows.
Obtaining the Mirror Shield
After completing the Mysterious Walls Sidequest and after defeating Vaati, fuse Kinstones with the Goron on the far right to make Biggoron appear at the top of Veil Falls. Warp to the Cloud Tops (it's the shortest way to the top of Veil Falls) and keep traveling downwards to the Veil Springs. Talk to Biggoron and he will ask you if he can chew on your Small Shield for a while. Let him, then go mess around in Hyrule for a while. Come back to Veil Springs, and once Biggoron has had his fill, he will spit your shield out again, but now, it's the Mirror Shield! Since you've beaten the game already, this thing doesn't have much use, but it's really cool looking, and it's fun to kill Octoroks with.