Thanks again @coelmay – that put me on the right path.
For future Googlers, my steps to get it working:
- Simplified my dependencies to be proper npm modules using Github Packages
- Added a
.npmrc
file to my app and committed it, but used an environment variableNPM_TOKEN
to reference the personal access token created for Github Packages (per these forum posts) - Added a
_redirects
file in thepublic
folder to handle React Routing per the docs. - Got rid of the Express.js server and everything works as expected, now.
Thanks!