Hello,
From a CNC point of view it definitely won't be a problem to get started with a KUKA arm, though you may run into problems like file-size limitations down the road.
As you wrote, the challenge is the handling of the robot - but for standard milling processes, that by itself won't be too bad.
The basic KUKA courses are good at giving you a broad overview of robot handling and safety, but don't go into the specifics. At the same time, getting a milling robot started doesn't require too many steps, mostly the calibration of tool and base which can be learned within an hour. It gets more complicated once you set up your own custom processes, connect devices via fieldbuses etc., but the start is not that hard, in my opinion.
Ideally you could tag along with someone for a day or two to get some hands-on experience. We do this sometimes, but are far away of San Francisco unfortunately.
We are working on an online platform, but it's also not there yet.
If you want to, send me an eMail and I can brainstorm some people in the area. But I'd rather not post contact information here publicly.
Best,
Johannes