Is there a best practice for "mocking up" resources/dependencies of a scene for single-scene development?

I'm working on a single scene that requires other scenes to have been run before it in the game (such as the login scene). What is the best way to generate the resources so that, when I run the game in the editor, I don't have to log-in every time?

Is there a way to "detect" when a game is running in development so that its initialized during development but NOT when running in production? I could temporarily set this stuff, but I'd prefer a more permanent solution.