Might need a LinuxCNC expert here - can LinuxCNC and the real-time kernel be easily installed on a Mint base installation? (I've only ever installed the LinuxCNC/Debian prebuilt package?

Reason I ask, John, is if not you may need to install the LinuxCNC ISO image similar to what Clive links to, in which case I wouldn't go too far down the path you're following, if you find yourself re-installing down the line