Top of the first book:
http://forum.barrowdowns.com/showthread.php?t=10385
Top of the first discussion thread:
http://forum.barrowdowns.com/showthread.php?t=10334
What happens next as Nimrodel relives the past:
Mithrellas, stung by Nimrodel's fury, will linger near her, til Imrazor finds her, courts her, and marries her. She leaves Nimrodel long enough to raise a family. ...
From the first discussion thread, towards the bottom of
post # 9:
After Mithrellas leaves Imrazor she returns to the mountains to look for Nimrodel. She travels far west (towards Lefnui?) and finds the wandering Nimrodel, and persuades her to return to Edhellond and look for Amroth.
(While Mithrellas was married to Imrazor and raising a family: )
Nimrodel has found Amroth's corpse (uncorrupt) washed up on shore, somewhere on the Belfalas. Since he is uncorrupt, she hopes in the possibility he might return to that body instead of being reborn as an infant, so she lays him in a few feet of clear water (a la dead marshes, only he doesn't rot) and waits (for a couple of decades) over his body for him to return.
But the Valar don't want to send Amroth back; They want her to come west; so they wait, hoping that she'll catch the next ship. Amroth is stuck in Mandos, waiting and hoping.
Nimrodel waits beside Amroth's body for a long time; however, Nothing Happens, (while Mithrellas and Imrazor are happily building a family, and Amroth is waiting in the Halls of Mandos for her to sail west.) and eventually Nimrodel despairs and loses her reason.
She returns alone to the mountains, where she finds the Stone of Erech. She waits there, drawn to it in her madness and despair, and the dead come. She recognizes their despair in hers, and chooses to stay with them, dwelling in her memories of Amroth while she is awake, and dreaming of him while she sleeps. In her madness she willingly participates in their curse. The Valar realize this and further refuse to send Amroth back to her while she is under the curse.
Mithrellas finds her, after a long hard search. She waits on her, and takes care of her. For long years they dwell there, til Nimrodel forgets her name and takes the names given her by the dead. but Although the curse burdens, opresses and wearies her, Mithrellas brings food to Nimrodel and never abandons her. When
Elessar breaks the curse and frees the Dead during the War of the Ring, Nimrodel and Mithrellas are freed as well. (Nimrodel is, however, still mad, completely living in memories of Amroth.) They wander west from Erech, through the cleft above the penninsula that juts into the bay of Belfalas, straight to the coast. They follow the coast up through Enedwaith over the mouth of the Isen, up into Miniriath, to the mouth of the Baranduin. There they halt; short of the havens, they turn south and return to Belfalas.
EDIT: or to the vale where they are now.
This progression, with the dreams and songs, should wrap up the tale. Hopefully we can use this as a framework, or as a warp, weaving in the woof of the dreams & songs as we go.