init.pp should be the single entry point for the module. In this way, someone reviewing the documentation in particular, as well as the code in init.pp, can have a complete overview of the module's behavior.
If you've used encapsulation effectively and used descriptive class names, you can get a very good sense just by looking at init.pp of how the module actually manages the software.
Modules that have configurable parameters should be configurable in a single way and in this single place. The only exception to this would be, for example, a module such as the Apache module, where one or more virtual directories are also configurable.
Ideally, you can use your module with a simple include statement, ...
