Hi M60A,
Thanks for the suggestion, but yes, I've tried Irish Spring soap, they just ate it . I've tried drier sheets, air fresheners, ultrasonic devices. I've tried plastic sheeting under the tires, putting the car on jack stands all to no avail. I often imagine the mice are laughing at me as I try all these things. Obviously, if I drove the car daily, I wouldn't be having these problems. But, also, some cars are just better buttoned up than others - I have a truck that sits out there in the driveway for weeks at a time before I drive it, and in 12 years I haven't found any evidence that a mouse has found it's way into the cabin.
Mice are looking for food and shelter (just like people). My XF sits in a 60 ft by 30 ft driveway/pad, near the N/E edge. Beyond the pad, on the South side is the house, on the other sides of the pad are open fields, hills and a road. We have hawks, coyotes, snakes, and owls hunting nearby, so the mice are looking for a safe place to nest. Strangely, this year we've had a lot of rodents, but no owls in the owl boxes, so that might be contributing. Unfortunately, my XF has a no crank issue which I'm only able to work on sporadically during the weekends (work and life get in the way), so it's been sitting for about a year. Yeah, I know that doesn't help, but it is what it is. I have fun troubleshooting, and learning about how a more modern car works, and since this is my wife's toy, I'm don't have the pressure to get it on the road right away although that's starting to change.