Similar to Sewickley Heights- forested, hilly, and pleasant. There's little through traffic, so it's generally pretty safe.
I used to run a six mile loop from my dad's house, which took me around Squaw Run East on the northwest side of the Shadyside Academy campus and the Field Club. That route, however, passed a treacherous stretch near my family's church that worries me a little, with sudden turns, so I combined it with part of a loop I have run with my friend Jess. Turkeys are sometimes an issue...
There's little more to say about the loop than it is pleasant, challenging and you can extend it with several loops around Squaw Valley Park, which is delightfully flat and has a nice crushed limestone surface. The turns are a little tight for workouts, but the loop is 1034 meters long.
There's a short trail through the woods to the east, but it doesn't go much of anywhere. You can also find the Trillium and Salamander trails off of Squaw Run Road.