Hi Luke,
I just read your last update [1], even though it is already three weeks old. It was a good and interesting read - thank you for that!
There you mentioned the bad shape of Free Software in the fields of CNC milling. In general I have to agree. But I think, it is not as bleak as you experienced it.
There is indeed a usable toolchain of Free Software for 2D or 3D design, toolpath generation and machine control. Sadly especially the toolpath generation process is far from being as fast and full of features as it should be. Personally I maintain PyCAM [2] (a toolpath generator). The toolpath generators are the weak link between a range of good libre 3D and 2D design software and linuxcnc [3] - an excellent and mature software for machine control.
Feel free to contact me, if this topic is of any practical interest for you right now.
Cheers, Lars
[1] https://www.crowdsupply.com/eoma68/micro-desktop/updates/progress-physics-ta... [2] http://pycam.sf.net/ [3] http://linuxcnc.org/