I used to ride through Crafton to/from Sq. Hill. Most times I'd just take Steuben all the way to the circle. The other route I used (a bit longer, but definitely less traffic and a little less steep) was Ingram->Prospect->Mainsgate->Berry->Straka->Chartiers->Steuben.
I didn't think the circle itself was that bad but taking the ramp onto and making a left off of Carson was easily the worst part of the trip. Walking might not be a bad option, I think there are stairs.
Once you're into the station square parking lots you can get on the trail, I'd take it all the way to Hot Metal, then make a right and go down to the Junction Hollow trail, and from there Boundary->Joncaire (steep climb + cobbles though...)->Bouquet.
If you want to ease into things, you can take a bus from crafton to station square - it definitely cuts out the hilliest and highest traffic part of the route, the rest is mostly on the trail. And, there are a lot of variations (Birmingham Bridge, Bates St., etc) you can try once you're more comfortable with the route.
good luck,