The mill "loft" is the hay area of the second floor, where the Secret Society girl will give you the Cosmic Symbols password card (you need the Princess' secret message from the maid's room in the castle). Above the loft is the attic, where the hovercraft is stored. To reach it, you will have to turn the windmill arms counterclockwise, which opens the roof dome.
(see related question)
How do you talk to the girl in the hay loft at astro knights island?
Climb into the loft of the mill and hang on the short rope there.
Climb into the loft and pull on the rope to release the gear lock. Then climb on the windmill arms so that they turn counterclockwise. This will open the roof dome. The hoverboard is powered by manure.
Climb into the loft and pull on the rope to release the gear lock. Then climb on the windmill arms so that they turn counterclockwise. This will open the roof dome. The hoverboard is powered by manure.
The hovercraft (hover board) is in the attic of the mill. Climb into the loft to release the gear lock, then climb up the windmill arms so that they turn counterclockwise. This will open the roof dome. The hoverboard is powered by manure.
The hovercraft (hover board) is in the attic of the mill. Climb into the loft to release the gear lock, then climb up the windmill arms so that they turn counterclockwise. This will open the roof dome. The hoverboard is powered by manure.
Inside the windmill, climb into the loft and hang on the rope. This will release the gear lock and allow the windmill arms to turn. Jump up on them to turn them counter-clockwise, which will open the roof dome.
Climb into the loft and pull on the rope to release the gear lock. Then go outside and climb on the windmill arms so that they turn counterclockwise. This will open the roof dome. The hoverboard is powered by manure, and will go to the mud swamp when activated.
The hovercraft (hoverboard) is in the attic of the mill. Climb into the loft to release the gear lock, then go outside and climb on the windmill arms so that they turn counterclockwise. This will open the roof dome. The hoverboard is powered by manure, and will take you out into the mud swamp.
You show her the message that you get from the castle (maid's room, first floor left).
It is in the attic of the mill. Climb into the loft to release the gear lock, then climb up the windmill arms so that they turn counterclockwise. This will open the roof dome. The hoverboard is powered by manure. Once fueled, it will position itself at the mud swamp, the only place where it can be used.
Enter the Mill, climb up into the second floor loft, and grab the short rope that is hanging down. This will unlock the gears, and the windmill arms will turn freely. Go outside and climb on them, turning the arms counter-clockwise to open the roof dome.