teachercd

Well said @ Toe.  You pretty much typed up everything I was going to say.  The only thing I would add is steering towards one owner cars if it all possible because then you can glean some additional info about the owner and tried to make an educated guess as to whether the car was taken care of or not.

What is the most amount of miles you would be okay with on a used car?

Depends on your budget, I suppose. I think my first car already had a six-figure odometer reading when I bought it. My last one was about 40k.