You can approach it two ways:
1. Head over to CMU via Morewood, cut across campus, and head up the hill at the golf course. You can avoid Forbes by cutting over to Darlington at the top of the golf course and taking that to Murray.
2. Head to Shady Avenue via Walnut and go up Shady or (better) Beechwood. Don't be shy about riding the sidewalk along Fifth to get to Beechwood, either. Shady is more direct (and arguably not much hillier) but Beechwood is WIDE and has a bike lane.