The trips from Conway Yard [ adjoins Conway, PA ] will run "west" [ geographically north ] to CP Wood, which adjoins the town of Homewood -- NOT the Homewood section of Pittsburgh, thank heavens. Homewood is just north of Beaver Falls on Rt 18, and immediately adjoins the Turnpike interchange. So from Conway the trains will pass "through" [ = next to ] Freedom, Rochester, New Brighton, and Beaver Falls, eg PA routes 65 and 18.
From Rochester to Homewood is uphill; speaking generally, the gradient increases: it's 0.39 % at New Brighton to 0.95 at Homewood. The train will probably run on the 'westward' track because of the track layout of the wye at Homewood, at least in the outbound direction, and I'm guessing back also.
I would suggest you reconnaissance the area beforehand; I can't think of a map that would be that helpful.
Hope that helps.
Have fun -- but don't trespass.
Best regards, SZ
Edited to add: The 'westward track' mentioned above is the one [ of the four ]nearest the road between Freedom and New Brighton. It seems like the logical* choice -- but we're talking about a railroad here, and NS to boot, so logic doesn't apply. Where they load / unload at Conway is a factor, too.
*Based on the track / turnout layouts at Rochester and Wood. There used to be a restriction that you couldn't go from 1 [ the 'eastward' track ] to the wye at Wood, which would suggest at least one direction would have to be on #2, the 'westward' track. I seem to recall that when Conrail turned excursions there they went west on the west, and crossed over to go east on the east. But that's from memory.