Thanks for the responses guys.

Ascension, that was the closest to parchment I was able to get. I'm using GIMP, and the 'Clothify' filter didn't look as good as the 'Apply Canvas' one did.

NeonKnight, I think something like that may be a little beyond my ability. Also, there are some spots on the torn edges that I'm not too happy with, namely the upper left corner, the area above Russia, and most of the right side. Unfortunately, I had forgotten to save my parchment base in a non-flattened file, so I was unable to go back and touch it up. I decided to plow forward with the GM said he didn't think anything looked bad.