While at Coney Island for "dogs" and the Scranton Hobby Shop next door, why not walk a block to the Radisson Hotel in the Lackawanna Station. The main dining room and lobby are in the the original waiting room and worth visiting. You can get a first class lunch there if you desire.
I'm not sure of the hours, but there is a great HO layout in the mall next to Steamtown with many scratch built structures of Scranton's past and the present.
You can always chase an all Alco D-L train if you catch one in the Steamtown yard.