The Shasta Daylight cars would be fine if the OP modeled post 1945 but his GS2 is painted in the as built pre 1945 scheme, complete with as built forward number boards. The 2005 Lionel cars were actually made for this particular engine. The GGD and K-Line cars would compliment the engine as well. All of them with the exception of the MTH cars are not easy to locate though.
Pete