I don't believe we could "write a book" on fall Preparation:laughing:
Other then routine maintenance--as in spring---what else is there.
Now if the OP was for storage--
(1)Change oil and grease entire machine.
(2)Either drain or completely fill tank with TREATED FUEL. And don't forget to run the engine until dry or until gas in carb is renewed.
(3)Remove spark plug/plugs and add Sea Foam or motor oil and spin the engine a couple of revolutions
(4)In the extreme, you could place jack stands under machine to remove weight from tires
And remove all drive belts to prevent "belt set" especially where a belt has a twist.
Now---personally I never do any of the above because I use my Lawn tractors practically year round.:thumbsup: