Are you in Manhattan right now?
I was yesterday, in Philly now! Any recommendations for a nice run?
Nice! Depending on how fast you want to run, Old City is nice for a scenic jog.
Schuylkill River Trail and Fairmount Park past the Art Museum is the best place to stretch your legs, albeit crowded. If you can get a little farther afield, get out to the Wissahickon/Forbidden Drive. Some of the best trail running you'll find near a major US city.
You have to run up the steps of the art museum and pretend you're Rocky, it's mandatory
Wissahickon isn't that far from narberth... And ace!!