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Walthers Waffle Sided Boxcar Walthers Waffle Sided Boxcar...
Walthers makes a nice waffle sided 50 ft boxcar.  I would suggest populating your pike with them.  They are very easy to put together, well decorated, and reasonably priced.  I find most of mine for $7-$8, but have paid $10 in the past.  They come in numerous road numbers in both Chessie blue and B&O tuscan red.  I suggest a half and half mix of yours for a prototypically correct mix.  The kit itself is 80% or so accurate, good enough not to worry about any of the minor flaws.

I would not suggest buying an undecorated one and decorating it yourself.  Here it is just not worth it.  All of the waffle indentations would be a pain in the butt to decal around.  Stick with the stock ones, they are good as is.

Below are some of my waffle sided boxcars.  Some details you may want to add to be more prototypical are consolidated stencils.  I added one to the bottom right pic, but not the others.  I did the bottom left one with a blue overspray around the roof, this makes it look more prototypical for a repainted boxcar.  The painters aren't worried about getting any extra blue on the roof.  The top right one is actually a #486143 that I overpainted some of the "4" with blue to make it #486113.  Since the C&O class goes from #486000-486199 it is a good change to make to get another road # out there.