Can this Rom be split into CHR & PRG and burned onto an eprom to make myself a physical cart from a famicom donor?
It uses CHR ram, not ROM, so there's nothing to split apart. You'd have to seriously hack the rom, or find a famicom donor that matches mapper 30 or 111, so I doubt it would be worth the effort, honestly.
so, this could go on a retroUSB UNROM-512 board?
I believe so. I haven't tested on that specific UNROM512 configuration (there's a little bit of variance between manufacturers), but it should work.