I have visited the windmill MANY times and turned the cage so it faces the canal (I think). The doors to the canal are not open though. They look open from the outside but not from the inside. I am guessing there are 4 positions for the cage to rotate to with one of them facing the way in. I have gone to the windmill and turned the cage one position, gone all the way back to the bubble, linked in only to find I cant get anywhere. Are those doors supposed to be open all the time or is there something I am supposed to do to open them?

It depends on which canal you are talking about ? There is the one "main entrance" that will always stay open and a second one toward the "arena". To be able to go that way, you need to do three things.

1- find the proper level,

2- rotate the central inside cage to the proper direction.

3- and open the corner exit to the arena which can be done through the left small red button. Note that the red button at the side of the right lever is defective and serve no purpose in Myst 5. When you push in the left red button, make certain it does go in all the way (click on it and hold until it goes well in)

That button was precisely the problem. I went up to the windmill and pushed it (probably for the third time) and watched the doors open.

Thanks!

Glad you made it. You are very welcome.