So looking at your SimEthereal code base @pspeed, you make extensive use of app states.
I read the doc on App States, and I think I'm not quite seeing the "forest through the trees" here. It seems like App States allows you to turn your game into a state machine, where each state is perhaps a different/distinct scenegraph with its own/distinct game objects. And that when you transition to a different state, essentially the scenegraph and game objects associated with that state all get paused, and the new state is initialized/resumed.
Is that (more or less) correct, or am I way off base? Thanks again!