Good question. Here is my idea below.
Have you installed R on Amazon? If so and you use UNIX system like Ubuntu, use whereis
to get the path to execute R on Amazon
For your R script, store it in the /private
folder and use Assets
All files inside a top-level directory called private are only
accessible from server code and can be loaded via the Assets API. This
can be used for private data files and any files that are in your
project directory that you don't want to be accessible from the
outside.
Assets allows server code in a Meteor application to access static
server assets, which are located in the private subdirectory of an
application's tree. Assets are not processed as source files and are
copied directly into your application's bundle.
Static server assets are included by placing them in the application's private subdirectory. For example, if an application's private subdirectory includes a directory called nested with a file called rScript.txt inside it, then server code can read rScript.txt by running:
var rScript = Assets.getText('nested/rScript.txt');
You can then pass the script along as input when you execute it on the server.
(ref)