One does not simply walk into Mordor – One looks at a map first!
What-the-Uruk was Gandalf planning on doing if he survived Moria and guided the Fellowship beyond Lorien? Specifically, how was he going to get into Mordor?!!
Tolkien may not have written Mithrandir’s plan down, but he seems to have left some subtle cartographic clues. Check out the analysis ( Gandalf’s Plan to Enter Mordor ) of the contour map of Gondor & Mordor in the front of The Return of the King.