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 mill is out of commission. The only way to get across the mud swamp is the hovercraft in the mill's attic.
There is no helicopter. There is a hover board in the attic of the mill that will get you across the mud swamp. (see related question)
The manure is used to power the hovercraft hidden in the attic of the mill. (see related question)
The boy at the farm near the mill will give you a bag, but only one. Use it to power the hovercraft in the Mill's attic. (see related question)
The boy on the farm just left of the Mill will give you a bag. You will use it to power the hovercraft in the attic of the Mill. (see related question)
The damaged saucer Excalibur has crashed in the mud swamp to the right of the Mill. You can reach it with the hovercraft (hover board) in the attic of the mill. (see related questions)
The saucer Excalibur is in the mud swamp to the right of the Mill. To reach it, you need the "hovercraft" (hover board) that is in the attic of the Mill. (To get it out, see the related question)
The hovercraft (hover board) will take you out into the mud swamp, where the saucer Excalibur has crashed. (see related question)
The farmer will give you one bag, which you use to power the hovercraft hidden in the mill attic. (see related question)
The fuel rod replaces the damaged one on the saucer Excalibur, which is crashed in the mud swamp to the right of the Mill. Get the hovercraft from the mill attic to reach it. (see related questions)
Use the hovercraft (hoverboard) that is in the attic of the mill. (see related question)
it is to the right of the castle, just keep going right.