Astral projection is great, but taking possession of a Guardian half a universe away is a job for a hero, not a ghost.

Simry enjoyed her escape from a world of shunning and rules that did not apply to her. Life in the Citadel could be difficult, but it had its rewards in the shape of education and friendships.
Being asked to seek out a Guardian and keep him sane from dozens of worlds away was one of the hardest assignments she had ever taken on, and it was also the most rewarding. She rescued the Guardian’s soul, kept his spirits up and made sure that he was able to survive until physical help could arrive.
N’kad was on the edge of giving up when the ghost entered his mind and took over his situation by lodging herself in his soul. The stranger in his mind was brash, annoying, and yet, she kept his attention every moment that she was with him. He would travel quite a way for a woman like that. She was his hero, after all.