I used to play with the Arduino controllers long before 3d printing came around. For car functions. Like I used an Arduino nano and a few 5v relays to make an autolamp module for my car. And I even used a mega to make a full bcm(body control module) for my old Honda. So I was already familiar with the Arduino environment and writing sketches and when I saw marlin I just identified with it. There are newer versions of it that you could use for your old ctc machine. I actually like marlin. I think it is really cool how everything is there and you just uncomment things to activate them or comment them to de activate them. But you never really have to write anything. maybe just change values.