My first full project: A movie scene of a dutch mill. Please comment

Hi forum,
My first Blender project finished rendering. It took 2 weeks on 2 computers and only then I noticed a few improvement points:
1- The begin and end does not fit nicely so repeated play gives a jump
2- The sails do not stay on the wood and go thru
3- The floor above the millstones should get transparent to show the wheels below it
These 3 things are now hopefully corrected but before starting the 2 week rendering again I would like to ask your advise for further improvements or errors that I did not see myself.
Thanks a lot for your help.

Rene

I already got one remark via YouTube: the (old) mill is rotating in the wrong direction.