15 years ago I made a post about modifying the Craig stereo for auxiliary input, I went further and gutted my Craig to replace it with a Raspberry Pi, modern LCD display and controls. I go into more details on my little website if you're interested: https://1561project.com/?page=fluxaudio
Not really intending this to be a "how-to" but more to give people ideas about what could be done. It was quite a bit of work, so would likely only appeal to the hardcore originality folks