Some excellent photos to be taken around the old Bethlehem Steel Plant (78 west to 412 North). Private property, but many good locations around town. Recommend Lehigh Pizza or the little Pub down by the Steel Mill entrance for good viddles...
The Selinsgrove Branch (west of Shamokin) provides some excellent photo opportunities (as do the co-eds at Susquehanna University).
Shamokin is a ridiculously depressing town to either exist in or photograoh, but if you are into photographing America's decaying glory days, then it'll fit like a glove. The clock from the old railroad station is lying on the ground amidst a pile of rubble. Looks like something more fit for urban Detroit than small town, PA.
Sunbury, also west of Shamokin has some excellent photo locations through the center of town.
Some old DLW MUs are rusting away in weeds just south of Route 11 near a tank a farm just northeast of Sunbury. Good ribs (excellent ribs, really) available at BJs in Danville, PA as well as Selinsgrove, PA.
PPL Shamokin Dam plant maintains an in plant switching operation to move hopper cars loaded with coal.
Recently reactivated rails between Lewisburg and Mifflinburg provide some beautiful scenery replete with local Dutchman or Menonites atop horses or riding behind them in buggies.
Enola yard by Harrisburg is very interesting and is worth a visit.
An abandoned coal operation in Treverton, PA (just west of Shamokin) has rails and some machinery intact and would probably be worth a gander.
Centralia, the famous site of an underground coal fire burning to this day, is quite interesting, and more than a touch creepy.
That's all I can think of. Hope it helps some. Many thanks are due for my ex-wife for having shown me all of these things and tolerated me actually being interested in trains.
Be well. Do good work.
Semperfidelis