If you don't already have something like Photoshop or Paintshop Pro, you can try one of the better free raster graphics editing programs, such as
Paint.NET or
the Gimp.
For the 35.5pixel/meter scale plans, scaling them to 555% will get you damn close to a 1"=5' scale on paper, using the poster printing setting (multiple sheets per page) of your printer. I printed a section of the
CR-0710 for use in my game at (roughly) this scale, and it worked out fine.
I wouldn't even think of trying such a thing with the 6.4ppm scale plans.
You're going to have to experiment with your printer settings to get it right, thus wasting some paper and ink, and the quality will be "OK" at best.