The best way to prevent rust and moisture on any surface is to keep it in an air conditioned space with good airflow around it.
Assuming you don't have a gun safe with a little heater in it, the best place to keep a gun may be behind or near the refrigerator; the air is as dry as the rest of the house, but its also warm from the refrigerator condenser.
I don't see a gunsock offering any rust protection, unless it had some lubricating property.
I think gunsocks only offer protection from bumps and nicks.
I'm in Ala and if I take a gun outside from a cool spot indoors during the summer, the scope fogs up and the metal sweats.
I try to put them in a place to "pre-warm" before I go outside.
Where the hot air blows out of the refrigerator is a good place to warm a gun.