I'd skip the poison/trap idea for rodents since they might just go die in the car (if they can get in). Maybe one of those battery operated ultrasonic pest repellers if you're worried about critters. I wish that I got taken care of as nicely as you take care of the car. (hint for my wife).
The Golden Rule
1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)