The wrong kind of details: the components of wonder (aka lmp's rant)

[Kuruharan]

Frodo also sees Sauron - in Galadriel's Mirror and upon Amon Hen when he wears the Ring - and more and more as he approaches and passes through Mordor. Other than that, I think you're explication is right on.

Quite right! I had forgotten.

Although I would categorize each of those slightly differently.

At the Mirror Frodo had a more visual encounter, but he was protected by Galadriel. Sauron did not actually make contact with Frodo. (I'd also argue that it was a lower intensity vision than Pippin had for that very reason. And for some reason I always thought that Pippin saw more than just an Eye, even though there may be little reason for such a belief.)

On Amon Hen Frodo only saw a shadow, but he was fully exposed to the influence of that Shadow and it was only through the timely intervention of Gandalf that he held up.

On the walk through Mordor I'm not so sure that I think that was a personal encounter with Sauron. Frodo was aware that Sauron was looking for him, he felt the presence of Sauron's Ring on his person, but the overwhelming, terrible Presence is absent. I mentioned this briefly at the end of my post on this subject.

Tolkien actually addressed this issue when he discussed what would have happened if Frodo had claimed the Ring. From his description of this supposed encounter I feel that there was a tremendous difference between just being aware that Sauron was somewhere in the world and being immediately before him (and him being in a bad mood at that!)

But in any case, Sauron was one of the most integral characters, but we never really "see the monster."