In the Projucer, I should just have to select which modules I want. No selection of module paths should be exposed to the user. After all, it seems like a bad idea to use modules that are out of sync with the version of the Projucer.
JUCE should just be distributed as the Projucer app (or an installer). The user should never have to worry about the locations of modules, as they would be included with the installation (much like how Xcode puts the C++ standard library inside its app bundle).
Does this make sense?