Has it only had one owner? Ask the seller for more information about why the car has so few miles. I purchased a 1987 in 2003 that only had about 60,000 miles on it, and the mileage was correct.
After a few phone calls and faxes, I found out the previous registered owner had personalized plates on it, and had three other cars registered to her at the same time as that one. After finding out that and her zip code I had no reason to doubt the mileage.
As another case, my friend just received his grandfather's 2000 Civic Si with only 10,500 miles. No reason to doubt that at all. A neighbor sold a 9 year old Buick with 6,000 miles before. My friend's dad sold a 1983 Mustang GT CV about 1996 with only 13,000 miles.
Some people just get a car for fun or don't drive much, and they no longer can afford it (whether space, insurance, or just too old), or they just don't want the car, or they get sick or die.
The real question is why do you doubt the seller so much? Make sure there are no problems, and don't expect any warranty to transfer regardless of legalese that says it will. I got screwed by the exact mistake of buttuming since a warranty said it would be transfered to a buyer, it actually would.
Dave