Welcome Don! Glad to have you here - and you are certainly starting off with a doosie of an image to fix...
The first thing I noticed when I downloaded it to see what could be done with it was that it is a Grayscale image.
Scanning to Grayscale, even with a b/w image, deprives you of the selection of channels available in a color image. Often, by examining the different channels you can find a more useable one where the damage is not as apparent.
I'd suggest always scanning to color. The image can always be desaturated later, and the channels are usually the very first thing to check when starting to work on an image.
Could you possibly re-scan in color and re-post?