Re: Winterizing?
Boost the tire pressure by 10 psi and use a battery maintainer not a trickle charger as you do not want to cook the battery. Or you could just charge the battery up every month and remove the cables.
Cover the car.
I'm not sure the critters will go too far up the OEM exhaust as I'm sure they will not want to get covered in soot, so I think that's the least of your worries.
A few mouse traps or whatever, keep these under surveillance or the first mice will get killed and the next mice to come along will get a free ride.
I start my car every month and bring it up to temperature and put the heater on.