About the only thing you would have to do is schem the radio, and modify the circuit for a TRS connector before the preamp. You would want to input the summed stereo signal from the geadphone jack of whatever device you plan to use with the radio and make sure that it is gain matched with the input of the radio to avoid overdriving the preamp. --Hopefully for the sake of longevity, your radio uses a straightforwards compliment of tubes in standard noval and octal sockets, not oddball stuff.
Also you may want to go through the circuit of the radio and replace the electrolytic PSU caps, and replace any resistors who values may have drifted over the years.
With the digital front end, if you want a touchscreen , you could rape a cheap android tablet, Netbook or Chromebook that has a touchscreen, or simply rape and repurpose an old smartphone.
If you go the smartphone route, bear in mind that some cell providers encrypt the bootloader. so when you root the phone and try to install a modified/ alternative OS ROM, you may wind up bricking the phone.
_________________
When There's No There to get to, I'm so There!