When are you thinking of doing this?

As of right now this is pretty much the detour.

https://maps.google.com/maps?saddr=L...&z=15&lci=bike


But in a few weeks, you will be able to pass through Sandcastle and avoid Route 837

Next spring you will be able to go from Station Square in Pittsburgh to the trail in Boston.

Let me know if you need help at this end. A tour guide and / or a place to stay.

Be aware of your arrival time by train. I would not advise going through Hazelwood, Homewood or Mckeesport after dark.