Adding another Ember application as a dependency

I have been tasked with adding admin functionality to an existing Ember application. I am trying to determine how best to break up, what could end up being, a very large Ember application.

The administration functionality is going to be feature rich and am keen to avoid standard users having to download all of the unnecessary admin code. The important consideration for the admin functionality is that it will need to include almost all of the routes that the existing application has.

I'm trying to work out how I can go about neatly breaking up the two codebases. Currently the best I have is to convert my existing application into an addon that can still be deployed separately.

To ensure I don't regret this decision in few years, can anyone suggest any better approaches to this?