When I stored my 72 Convertible, there was a field across the way and mice ended up dragging pieces of walnuts and various other crap into my air cleaner snorkel.
so block that one off for sure
I'd stuff a stout rag in the exhaust as well.
Water vapor settled in the lowest point of the exhaust and probably froze and unfroze 100 times. Last year I drilled a couple 1/8'' holes at the lowest point, and then plugged them back up with stainless screws in the spring. It gets really foggy sometimes in the fall.
I put a light coat of sewing machine oil on my caliper seals and rubber hoses with a paint brush. And spray the rotors and inside of drums down with white lithium grease.
Sewing machine oil on all hinges and contacts
A battery disconnect, full tank of premium gas with Plenty of Stabil and carb cleaner. (I put a little bit of paint thinner in too)
A few drops of Upper cylinder lubricant in the spark plug holes. I used the red motor break in stuff once and the lucas stuff once, both were fine. Red stuff is much sticker though.
Dielectric grease on battery terminals and cables, the starter contacts, and the coil plug.
I put 4 crappy rims and tires on from the boneyard so I don't get any flat spots on my Kellys
I also put a piece of cloth between the rim and rotor so they don't get stuck together. Anti sieze or grease the middles so they don't stick either.
Some people use stands, but I don't like having the total weight of the car focused on 4 little points of contact.
(Kinda like women's high heels cause more damage to concrete than 18 wheel semi trucks.)
If I'm not going to be starting it up, I'll over fill my oil a couple of quarts, and drain it in the spring. Save the storage oil for your buddies/your beater cars.
Hit the grease fittings.... U joints too.
I brush little oil on the underside of the belts while it idles.
Spray some tri-flow on the steering linkage, and A-arms.