I am making a role playing game for fun and attempting to use TDD while developing it. Many of the TDD examples I see focus on creating the test first, then creating objects tha
TDD is about design! So doing TDD you will be sure that your design is completely testable.
Also, the "balanced approach" is the way to go IMO. You already know a high level architecture and TDD will drive this architecture to be testable.
EDIT: Although, if you want just to practice TDD I would not do the "balanced approach". I would just do TDD with "baby steps" and maybe coding Dojos