go into the room that(to me) looks like a fun rollercoster and go through that and at the door up stars is the door w/ the boss key if you look really close, there is a door behind the chest conaining the big key. First, go to the door that led to the room where you found the spinner. instead of going through it, find the place on the wall where you can ride the spinner. after you ride it to the next door, go through that room and you will find yourself in the room that contains the big key.
day fly
Use the spinner and go on tracks then press A to jump off.
both are in Guerdo desert.
The mirror of twilight is in the desert. you gain access through the mirror of twilight after defeating the boss of the desert temple.
Arbiter Grounds and the Mirrior of Twilight
there isn't one
A place called Arbiter's Grounds in the desert
to the bridge of eldin
This dungeon, located in the Gerudo Desert, is the Arbiter's Grounds.
You get it in the arbiter grounds.
There isn't an Outset Island on Zelda Twilight Princess only in Zelda Wind Waker and other ones.
After beating twilight princess you don't get anything.