Danville is a very busy place and if you monitor AAR channels 84, 94, 12 (CSX), and 22 and 76 (NS) you shouldn't have much trouble finding trains. The busiest location is at "Danville" proper where the CSX and NS cross at grade just SW of the intersection of Voorhees Street and Bowman Ave. All NS trains have to contact the Tilton yardmaster and the CSX dispatcher to get thru town. There is also an interchange yard located just north of the diamonds known as North Yard. All this is easily accesible. Other highlights include CSX's Brewer Yard on the SE side of town and NS' Tilton Yard on the SW side of town. You can get between both yards using I-74. You should also monitor AAR channel 7 for any KB&S activity. They have a small interchange yard at Newell east of Danville just north of where the NS bridges the old ex-MILW mainline.
BTW, my avatar is a photo of NS #255 at Danville. Check out Danville on RailPictures.net for ideas on photo locations.
NW: The Darth Vader Railway