I’ve tried the repellant by Ortho and it didn’t help. What kind of mats are you referring too? I would be interested in trying it if you believe it would work. I would prefer that to taking it for a long car ride up the mountain.
BTW, I have never mistreated an animal. Just wanted to be clear on that.
Google for ScatMat and similar items. I’ve never tried it, but it sounds like it would make a surface unwelcoming for a cat.
Another answer might be to keep a dog under there (maybe only for a week or so).