Gimli first: The last paragraph of Appendix A in
Return of the King reads,
Here follows one of the last notes in the Red Book
We have heard tell that
Legolas took Gimli
Glóin’s son with him because of their great friendship, greater than any that has been between
Elf and
Dwarf. If this is true, then it is strange indeed: that a Dwarf should be willing to leave
Middle-earth for any love, or that the Eldar should receive him, or that the Lords of the West should permit it. But it is said that Gimli went also out of desire to see again the beauty of
Galadriel; and it may be that she, being mighty among the Eldar, obtained this grace for him. More cannot be said of this matter.
So
Tolkien leaves the matter understated: He does not
positively say that Gimli reached Tol Eressëa, but strongly suggests it. Gimli was at this point 262 years old: quite old for a Dwarf of
Durin’s line! The average age of the
Dwarves for whom we have data, and who were not killed in battle, is 259 years, the median (most common age) is 251. The longest-lived Dwarf was Dwalin, who is said to have lived to be 340, a matter on which Christopher Tolkien remarks at one point, because the
next oldest Dwarf of whom we know is Borin, younger son of Dáin I, who lived to 261: Gimli is older even than that. He wasn’t going to live much longer.
Legolas and Gimli left in IV [Fourth Age] 120, SR [Shire Reckoning] 1541, soon after
Aragorn Elessar died. Rose Gardener,
Sam’s wife, had already died in IV 61, SR 1482. The notation in Appendix B, “The Tale of Years”, says,
Death of Mistress Rose, wife of Master Samwise, on Mid-year's Day. On September 22 Master Samwise rides out from
Bag End. He comes to the Tower
Hills, and is last seen by Elanor, to whom he gives the Red Book afterwards kept by the Fairbairns. Among them the tradition is handed down from Elanor that Samwise passed the
Towers, and went to
the Grey Havens. and passed over Sea, last of the
Ring-bearers.
Now we know that
Elves continued to migrate to
Aman from the Grey Havens after
Gandalf,
Elrond, and Galadriel departed. One of them was
Celeborn, who several years after the departure of Galadriel grew weary of
Lórien and moved to
Rivendell, where his grandsons Elladan and Elrohir still resided.
My personal opinion is that Elladan and Elrohir, like
Arwen, chose mortality: strictly speaking, to retain their
Elvish longevity, they had to leave Middle-earth with their father or forsake it; however, I am aware that strict interpretation might not apply. In any case, I think Celeborn joined his grandsons while they remained in Middle-earth, then departed after their deaths.
I mention this because when Aragorn dies in “The Tale of Aragorn and Arwen”, Aragorn tells Arwen that their decision to face mortality
was made … in that day when we met …in the garden of Elrond where none now walk.
Elladan and Elrohir had been living in Rivendell with Celeborn, but none were there now. Had they taken wives among the women of the Dúnedain, we do well to remember this: the
Kings of
Arnor lived shorter lives than the Kings of
Gondor by about one year in four for the northern line, or one year in five for the southern. (I.e., the ratio is 4:5.) Aragorn lived to 210 years, which is in line with what we should expect for the first
King of Gondor at the beginning of the
Fourth Age. (See my essay on this, “
Decline of the Lifespan of the Númenóreans”. I mention that, “The distinct declines in the lifespans of the
Númenórean rulers appear to be straight-line calculations,” and suggest that Tolkien might have prepared a chart from which to read the
ages of the kings still among his papers.) That suggests that any long-lived
Dúnadan in Arnor would die at about age 168. If Elladan and Elrohir married Dúnedain wives younger than 50 at the end of
the Third Age, they would be expected to live to about IV 120. We know that Gilraen, Aragorn’s mother, was considered “young and had not reached the age at which the women of the Dúnedain were accustomed to marry” when at age twenty she consented to marry
Arathorn II son of Arador; she was twenty-two when Aragorn was born, and she was 100 when she died in III 3007, SR 1407, twelve years before the Company of
the Ring and six after
Bilbo’s Farewell Feast, “aged by care, even as one of lesser
Men,” as she told Aragorn. (“Tale of Aragorn and Arwen”)
My wandering point here is that Elladan and Elrohir, had they chosen mortality and taken wives among the
Dúnedain of the North might also have died by the time Aragorn died, for it seems Arwen does not consider returning to her brothers; and their father’s garden, where it seems the brothers had only recently dwelled, was abandoned. (Though perhaps Aragorn is being merely poetic in his description.) The Tale says that
Galadriel had passed away and Celeborn also was gone, and [Lórien] was silent.
(That, I suppose, implies the Elves there had crossed the river to join their kinsmen in
Thranduil’s kingdom in
Mirkwood renamed
Eryn Lasgalen,
Wood of Greenleaves.)
But the
Elves of Rivendell, and of
Lindon, along with any that chose to leave Middle-earth who lived in Lórien or in Thranduil’s kingdom, were still permitted to depart, either from the Grey Havens in the west, or from the southern coast of Gondor, as did Legolas.
Círdan, it is said, remained until the Last Ship sailed. Any ship that departed the Havens would permit Sam passage at the direction of Círdan, who received his instruction from Gandalf.
A final note: Bilbo,
Frodo, Sam, and Gimli
died in Tol Eressëa. They did not become “immortal” like the Elves. They spent their final years among the Elves on the Lonely Island, and then they passed on to their destinies: Gimli to the
halls of waiting set aside for his folk by
Aulë, Bilbo, Frodo, and Sam beyond the circles of the world.
I believe just about all 
