I was going to wait until everyone chimed in before I replied.
To be perfectly honest I've been at this for over a decade and I've never found a really good solution for remote management.
I mean yeah you can use remote desktop, but it's slow as hell and won't properly display half of the front-ends/emulators that we use. A shared network drive works, but it'll slow down your bootup considerably and it means that your cab needs to be connected to the network, which may or may not be possible depending upon your location.
But ignoring all of that, you'll set your mamecab to boot into the front-end of your choice and shut down when you exit said front-end. So regardless of the solution, you typically have to whip out the old keyboard and mouse to halt this process and get into the pc's innards.
So my recommendation:
Mount a usb hub just inside the coin door... put a roll-up keyboard and mouse in the coin door as well. When you need to add/update stuff simply take a usb stick and fill it up and take it and the keyboard/mouse and plug them in prior to starting the cab. Then bypass the fe and go to town. Sometimes old-school is still better.