: Tolkien described a primitive Numenorean worship of Iluvatar in one or more of his letters. He also discusses how the Elves revere the Valar in THE ROAD GOES EVER ON (sort of as intermediaries, I think). Of course, Isildur was betrayed by the Dead Men of Dunharrow who had worshipped Sauron during the Black Years, Sauron perverted the Numenoreans and induced many of them to practice a Morgothian cult which involved human sacrifice, and Tolkien somewhere suggests the Blue Wizards may indeed have started or somehow been responsible for cults of magic.

: I would say there was a lot of room for speculation.

I've puzzled over this aspect for a long time. JRRT was a devout Catholic, and that presents a problem for some one writing a story taking place in pre-Christian times. The best theory on "religion" in LOTR was from Richard Purtill in 'Lord of the Elves and Eldils'. In the chapter entitled (oddly enough) Religion In Tolkien, he says,

"...If he shows his people at worship, for instance, who is he to show them worshipping? A man of Tolkien's activity of mind could invent fifty pantheons, with appropriate myths and rituals. But this would be to show his heroes worshiping false gods. Is he to make them monotheists then? But how is he to make their monotheism plausible? None of his races have a philosophical bent, like the Greeks. Is he to give them a special revelation, like the Hebrews? But if so, how is this to connect with Judeo-Christian revelation? Wisey enough, Tolkien does not show his characters at worship." (Purtill, 1974, Zondervan Books, pp 115-133)

Purtill points out various parallels between Elbereth and Mary and other "hints" of religion in LOTR that would be meaningful to a Catholic, though I'm afraid most Protestants (myself included) would miss many of these points. And while Purtill makes a fairly good case, it is sometimes easy to make connections that may or may not be valid. On the one hand, substituting Mary for Elbereth, while it is not exactly "allegory", it indicates a conscious act on Tolkien's
part. I don't know if he ever suggested any connection between Mary and Elbereth in his other writings, but I doubt it. Not only that, but the goddess Ishtar could fill in nicely as the model for Elbereth, which is even more unlikely in my opinion, than Tolkien knowingly placing Mary in the story. I do suspect that Tolkien's religion DID affect what he wrote in some ways. And Tolkien addresses the problem of life experiences affecting what was written in the Foreward to LOTR.

Not only does JRRT not show any one at worship, but there are no temples, churches or other "sacred" places in LOTR. I can understand this when looking at the Elves. They possibly viewed the entire creation as a sacred temple. Men on the other hand weren't as close to the "creator" as were the Elves. But they (at least some of them) buried their dead in tombs along with artifacts, which would indicate they expected the deceased to have need of weapons, jewels and clothing in another life. But why? The fate of "man" was a big question mark, known only to Illuvatar, so what prompted men to bury their dead in such a manner? Life after death was expected or at least hoped for. But what kind of life was not known (as I recall). The eventual fate of men was separate from that of the other races of Middle-Earth (which may or may not have been a plot device to explain why we don't see Elves, Ents and Hobbits today). I know there are plenty of holes in my reasoning, especially considering that I don't have enough of Tolkien's writings (other than LOTR & The Hobbit) to make a truely educated theory.