Bad news for now. While I thought in the end it would be easiest if I simply install Windows on my PC again, to avoid the pitfalls of cross-compiling and virtual hardware, in practice it isn't so simple.
My Win8.1 pro is refuses to install on the space I've designated for it, and while after numerous attempts and fiddling in the BIOS I finally got it to spit out at least a more specific error code (0x8030024), the suggested solution (to unplug all disks except the one installing to) is too much trouble for me (as the other disk in my case is an M.2 SSD screwed to the mainboard).
So either a VM it is, or the cross-compiler. But not today.