In case this helps anyone:
https://github.com/zeroasterisk/PhoneGap-BarcodeScanner-Example-iOS
Specifically:
Installed the plugin (in a handful of paths) but kept the one which worked. Implemented a basic JS scanner code to demonstrate functionality: auto-runs on load, auto-reloads on error, alerts on success/failure/cancel.
NOTE: the comments on the barcodescanner.js and index.js, both mention my customization of the define/require object paths. I could not get the demo/example paths to work, after several permutations.
(this is iOS only atm, but I plan on making an Android example too)