Controller for old Shopbot

Hey guys,

I've had this old old shopbot machine that was given to me for a few years now.... and have been working on and off on a controller.  I started with the idea of a 4 axis controller using an arduino mega using some flavor of GRBL/GRBLHal.  Got way down that trail and lost interest. Debating on selling this but before I do thought I may try something from LinuxCNC. (It would def be worth more with a functioning controller) Dont want to spend much, would still like doing 4 axis and have one end dedicated to turning.... Suggestions for a cheap controller to go with this? I have tons of computers that I can get my hads on. The current laptops I have do NOT have parallel ports, and would prefer to stay away from that technology. They do have usb and nics. Would like to keep the whole device inside this old Mac case, but if not thats ok. Here is my full album of pics if you want to check it out.
photos.app.goo.gl/T9CDbzShe9Yw5Ggw5

Any suggestions greatly appreciated!
 

Thank you Tommylight! I had seen a lot of recommendations for a Mesa board of some type.

If paired with the Mesa, and everything working what would it be worth to sell? Anyone?