And it is rumors gone amuck. I guess when people saw her laying there, they thought she was in the house of healing. I think she's in a boat. Maybe... (and this is a huge maybe) it's a vision shown to Aragorn through the palantir... Oppose me, Sauron says, and I'll cause your Evenstar to fall into a deep sleep, guarded by the dwarves, and awakened by a Disney Prince.
That is one way you could work her in the story. She seems fierce, so if she goes to Helms Deep, I won't mind at all. As long as she doesn't turn into Xena.