LotR -- Book 4 - Chapter 03 - The Black Gate Is Closed

[Essex]

Originally Posted by Lalwendë

One question always haunts me. What other entrances are there? Could they have got in from the North, or the East? What would have stopped them apart from the urgency of the task?

This has always intrigued me as well. Why not walk diagonally across the marshes and come around to Mount Doom from the North East? (or even go further south and approach from the South East?)

Do you think Gollum already had a notion in the back of his mind that he would lead the hobbits to Shelob, therefore he did not raise the possibility of another entrance?

Did Gollum know the black gate would be guarded as a stronghold and therefore impossible to pass?

Did Gollum actually know where the eastwards passage of the mountains ended anyway, and that there was an 'easy' entrance to mordor from the East?

As you can see, I'm raising more questions than answers here. Perhaps someone has the answer.....