Thanks flgrl17, these look familiar and this thread is (sadly) so long in the making. My guess is 100+ prints was more like it. So "partial print" was either hers or was said to not spook someone. Unfortunately, as we know, not finding matching a print doesn't mean it wasn't someone she was acquainted with, either daily or once in awhile. I'm excepting the family and boyfriend by saying that. But I'd sure like to know where a few other people, not including the workers, were in those two days.
It'd be interesting to know the mileage of the car from the last fill up. Unless she usually paid in cash, her credit card would show where she filled up and could trace to the likely # of gallons. I'd start with assuming it was topped off. Then from that station to the Mosaic etc.