I'm currently rewriting Ghostwalker, as I've said before. It's going reasonably well, but the further I get into it, the more I'm changing. Small changes at the outset of the story ripple down throughout the narrative, which means scenes and conversations between characters are having to be re-written. In addition, I'm changing some of plot points; people still get from A to B as before, but how they get there has changed. I'm doing this to (hopefully) make it more believable, and to simplify the story, make it faster paced and to move around some of the revelations within the story to make them a little more natural.
The result is an absolute pain of a re-write. I just hope it's worth it.