I rode to Monroeville a couple weeks ago. There are routes through Braddock which are fine. I don't think I've got a map with the route on it, but I'll see if I can describe it. The idea is to go along the hillside in Braddock to E. Pgh, and then down into Turtle Creek. So from Braddock Ave, turn left onto Woodstock at the light before going over the tracks. Jog right on Middle and/or Walnut, then left on Bell. Bell turns into Center in E. Pgh, where you jog right one street (don't get on 30), left under the underpass and down into Turtle Creek.
Then you know where you are. I took James Street up to Monroeville, and Thompson Run Road back. Had to cross 22 in Monroeville to get to Thompson Run but it was worth it. A classic Pittsburgh road, full of old industrial equipment, now with plants and wildlife springing up out of the wreckage. There's a small piece of truly abandoned road at the top of Thompson Run but sadly it only goes a half mile or so.