Well, as it ended up we are too out-of-town to take a subway without very specific instructions and there was too much luggage. She took the shuttle crdle mentioned that went from JFK to grand central station to Newark. It was $24 and she paid in advance. Down side is that she had to walk a block at grand central to wait for the next shuttle and with the non-direct flight she took this morning she probably could have driven in less time.
Thanks so much to all for your replies.
And btw, if anyone comes to Chicago, we would be happy to pick you up from the airport.