Well I just checked and if I chose to take the Penn/CL option adn the layover in Pitts, there is a chance if the walk isn't to bad I could grab me a bite to eat at place called
Primanti Bros which is a Pitts landmark and not quite a mile from the train station...now trying to find out what the area is like and how safe it would be to walk down, but this chance increases the odds of taking this option.
In Pittsburgh the train station is at the northeastern tip of downtown, in a region commonly referred to as the "Golden Triangle". The area is generally safe at night, just use some common sense (i.e. seek out areas with many people, avoid isolated areas, etc.).
The one potential drawback to the Pittsburgh layover option is that you will be on the CL for less than 10 hours, which may limit the amount of sleep you will get, depending on your sleeping habits. For me, if I were to take the CL solely between Pittsburgh and Chicago, I might have to skip the meals in order to get enough sleep during the trip.