stabil makes a spray now for inside the cylinders, not sure how much it is, but it is meant for burning off instead of having to clean it like you would oil.

wd40 is not something I would use regardless.

if you could actually "seal" it in a plastic bag, you wouldn't have to worry about moisture, but I mean actually seal.
then throw in some desicant packs before you seal it and you should be good to go.

cheap "heater" 20 watt light bulb. not cfl or led, and actual light bulb.

put the motor on something to insulate it from the ground and then put a box around it with enough room for the bulb somewhere and leave it on.
use some sheet rock to insulate. should keep it warm and dry.