No, nothing on npm will help you here.
Best I can do is suggest you do a local (not global) npm install into a known directory
mkdir temp
cd temp
npm install node-red
Then zip up the temp directory copy it over to the unconnected machine and unzip it.
You can then try starting it by running:
cd temp
node_modules\.bin\node-red.bat
But you are going to have other problems, once installed it will be hard to install any extra nodes as the catalogue manager will not work.
You will need a connected machine to install the modules then zip up the content of the userDir and copy that over as well.
I believe others have got this sort of thing to work, but it would be a lot easier if you could set the machine up with it connected to the internet first, then move it to the air-gapped network.
