Franklin Ave. Bridge is a good place to see the GE interchange for both CSX and NS. CSX is right underneath the bridge, and you will see NS if you look east from the bridge. I've seen close up shots of locos sitting on the NS interchange, but not sure behind which business exactly the photogs. accessed that area.
To see GE testing, (From Franklin Ave.) travel east on RT20 to the town of Harborcreek. Just before the WalMart, there is a small municle park on your left that consists of a few benches and flowers.
Not sure you can actually get shots of the back of the GE plant.
Other places of interest:
Lake Shore Railway Historical Society-farther east on RT 20. Once in North East, make a right onto Robinson St., and take that to the end. Museum right in front of you. CSX and NS both well visible from here, plus knowledgable company if you are looking for some. (Check your PMs)
Also from the museum, travel a few miles farther east on US20 to Bort Rd. There is an old 84 Lumber at the intersection. CSX goes underneath, and NS has a grade crossing about 50' away. If you get to the I-90 interchange, you only missed it by a few 100 yds.
There's a lot of other good places too, but these are my favorite/routine spots.
If you use ascanner:
161.250 NS road and disp
160.860 CSX road
161.340 CSX NH disp
160.590 East Erie Commercial (GE)
161.100 " " "