Hi
I use a lot of Photoshop, and remaking the board wouldn't be all that difficult. The bigger question I have is why would you spend all that time remaking it when according to the website at...
http://www.sol20.org/articles.html "The article offered free copies of the PCB artwork and drilling guide for the price of a SASE. Glenn Herrmannsfeldt did so back when and was kind enough to send a copy of it for this web site. It should be noted that this isn't he final design and in fact is reported to have quite a few errors."
But if you want to continue, open Photoshop, go to file, and click open. Navigate to your page and open. It will come up with a screen to set your preferences. Use 1200 dpi, and cmyk color, then click on the page you want to open. You'll need to adjust the size of the picture to coronation with the dimensions given in the file. Click on Image, then Image size and manipulate document size until correct dimensions have been achieved.
Now onto the artwork, make a single pad as a layer. Duplicate the layer 8 or 10 times to make a complete chip. Move them to the appropriate places and merge all those layers. Now you have 1 chip. Duplicate that chip 50 times and move them into place. Do the same for the other chip types and you're almost home.
The thin lines will likely be around 20 pixels thick. The thicker ones likely 40. You can do the same thing with layers for North south lines and east west lines. All that's left is the corners and turns.
There's a lot of assuming that the dimensions will be correct when it's made to correct scale. I don't know that they are, but when I redraw artwork like this, that is how I would do it. You will need a seriously accurate printer to get the 20 pixel lines to show up at 1200 dpi, and make it between the socket pads.
Best of luck,
Sven