There’s a scene in The Two Towers where Sam and Frodo are in the Emyn Muil (sp – the Hills) and Sam says something like, “I don’t think Gandalf meant for us to come this way.”
Which makes me wonder… how did Gandalf plan on getting into Mordor at all? That is, assuming he didn’t “die” in Moria, and also assuming that the Fellowship was not sundered at Rauros.
I think we pretty much have to assume that the Mountains (both Ash and Shadow) are nigh impassible, unless there’s a pass (how’s that for a tautology?) So it seems to me that either:
(a) They would have had to have gone east of the Ash Mountains and come into Mordor via Southern Rhun
or (b) They would have tried a gate/pass.
(a) seems unlikely, as that’s a lot of plains to go across (i.e., not much room to hide). Also, I’ve always thought of Rhun as Solidly Sauron, so The Fellowship probably would have been caught. Plus, it would have taken a long time! Still, I bet Sauron wasn’t watching his eastern side TOO much…
(b) Well, okay, there’s Morannon (and then Isenmouthe, after crossing Udun), and then there’s Minas Morgul/Cirith Ungol. The Morannon seemed pretty damned impossible to get in. I guess that leaves Cirith Ungol.
So my thought is that Cirith Ungol seems “easiest,” Shelob notwithstanding. (Although I can’t imagine Gandalf would have been able to take her out without alerting the Nazgul. Still, Aragorn, Boromir, Gimli, Legolas, Anduril and Glamdring would have been mean to Shelob, methinks.) I rank the “end around” as a slight possibility as well.