Further thoughts - chase a train or two into the East End, but spend your day around Michigan City. You'll see some freight action, particularly around the freight yard on the former NKP north of Shops, and the other freight yard, on the west end of town. The main between Dune Park and Michigan City is very interurban-like, too. Single track in the woods. Also, MC has some Amtrak, CSX, and NS diversions when CSS/NICTD gets quiet.
The folks at South Shore are pretty cool about railfans, but please don't take that as a sign to trespass or pester. It's only going to take one guy getting hurt before the entire employee base goes anti-railfan.
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