While I would certainly use plenty of caution with craigslist, I don't think it's that odd that someone might be willing to drive that far for a cat. When I was looking for barn cats I was specifically looking for cats that couldn't be housepets. At first I tried a rescue that placed feral cats as barn cats, but the two they placed with me took off and were never seen again. I finally found a couple of semi-feral older kittens that have worked out well, but believe it or not it wasn't that easy to find what I was looking for. For an already neutered, vaccinated cat that's a good mouser and used to living outdoors - I'd drive 40 miles if I were still looking. Heck, where we live, my daughter's high school is about 25 miles away. Forty miles - that's nothing for us.