The Pennsylvanian is really used as a day train from NYP-PIT, with Chicago passengers transfering to the Capitol Limited at PIT. Amtrak doesn't offer a ORL-PHL-PIT-CHI routing since you'd be taking the same train at PIT that you would transfer to at WAS.

I wouldn't go out of my way to take the Pennsylvanian from PHL-PIT, instead I would consider fitting in the Cardinal to your trip, which runs from WAS-CHI. The Cardinal takes a scenic routing through West Virginia and does have a sleeper available (wheras the Pennsylvanian does not). Taking the Cardinal wouldn't cost you that much time and should be an easy transfer from train 98 (provided he's less than 4 hours late). Train 98 arrives at 7 AM and train 51 departs at 11:00 AM and it is a published connection. The Cardinal only runs 3x a week