I'm glad you enjoyed it.
My guess on the platforms is that I assume the car was purchased to use on their tourist loop railroad and the platforms looked more "old-timey." Then again, I don't know what use a baggage car would have for a tourist railroad unless they planned to cut out (a lot of) windows for passengers. Again, this is all guessing. I only know a little about the Nebraska Midland's history.
I wondered the same thing about the windows. Photos of one of the other DSP&P baggage cars (No. 40 or 41) show it with two more windows (and short door) between the two side doors. Those didn't show up on the inside of No. 2 when I looked, though.