[Legate of Amon Lanc]

Originally Posted by Macalaure

And wouldn't it have been an incredible showdown for Gandalf and the Witch-King if they would have done a magic song contest at the Black Gate like Finrod and Sauron used to?
He hissed a song of wizardry...

You are right, I'm gonna write it. "Alternative road", only I think, Mouth of Sauron would be more appropriate to counter Gandalf's spells. Then, for the sake of Peter Jackson, Arwen could come and release the Fellowship from the darkness of Durthang...

Originally Posted by Macalaure

I don't think there was another way to pass the Ephel Dúath.

Originally Posted by Macalaure

Why did the fellowship try to pass the Misty Mountains by the pass of Caradhras?

`The questions that you ask, Galdor, are bound together,' I say. Here I think is the answer: as the Fellowship didn't attempt to pass the Misty Mountains any other way than through the pass of Caradhras, so they would probably not choose other way through Ephel Dúath.

Originally Posted by Macalaure

I mean, the Misty Mountains are an incredibly long mountain range, so it is quite hard to imagine there was no other pass south of Rivendell, preferably crossing a mountain with a more trustworthy reputation.

Concerning other passes through Misty Mountains, I can assure you that Caradhras was not the only one - there were many. But they were not so good for use. The Hobbit, Chapter 4: Over Hill and Under Hill, these are the first words of the chapter:

There were many paths that led up into those mountains, and many passes
over them. But most of the paths were cheats and deceptions and led nowhere or
to bad ends; and most of the passes were infested by evil things and dreadful
dangers.

The answer is here. The passes through Misty Mountains were rarely used, no maintenance, you could not tell if the path is even still there, or if it is not infested by Orcs. Although Caradhras might have had bad reputation, it was the best choice, at least for the Fellowship's needs at the time: because the pass was more to the south (which would mean going along the western side - safer, generally - as long as possible, and also not so much snow danger, although as we know everything can turn round), the eastern end of the Redhorn Gate was close to Lórien (where the Fellowship wanted to go), and probably it was the safest way in the meaning that there was lesser possibility of it being guarded by Orcs or whatever - as Gandalf says, the Enemy would not expect them to go that way. Also remember that before the Fellowship departed, scouts were sent all over the land and I think it's safe to assume that Caradhras came out as the best choice after considering all the information gathered.

And the Mountains of Shadow? I think it was more or less the same, and thinking about what you posted brings me again to conclusion that even Gandalf or Aragorn could not have had other options to cross the mountains of Mordor, even if they have known of some passage, they wouldn't risk passing it. There were no scouts who could explore the passes of Mordor, and Gandalf&Aragorn wouldn't know if a band of Orcs had not built a tower right at the end of the pass they wanted to use. So I think now it's finally clear that whatever way the Fellowship wanted to use, Ephel Dúath or Ered Lithui would not be the option even if there were million passes in them.