Well, I'm not so much of an expert on the L&N, but I can tell you that there are numerous yards along the line, as well as several small coaling operations on the northern part. It also has a high number of grain elevators along the line. For the yards, I would use something along the lines of an SD40-2 switching a few boxcars and covered hoppers around the yard. Along the middle of the line, in a town called Bowling Green, there is a plant that manufactures Chevrolet Corvettes. If I were you, I would have a train full of nothing but Autoracks (it's actually prototypical for trains around that area). Generally, freight patterns usually consist of Intermodal and mixed freight. Also, along with the Corvette plant, there are numerous factories along the line. Maybe you could have a small factory that has a few boxcars and a CSX switcher sitting outside.
Remember, I'n no expert, but I'm sure someone here is... I hope this helps anyway!
-Brandon