I have the plan for the story's bad guy, too and my mind is percolating on how to rescue Giles from the Book of Midnight darkness.
I still have to address Tara's 'anti-animal spirit' potion and Xander's refusal to drink it due to the deal he made with Hyena in "Rebuilding" and, of course, Spike's less than understanding reaction.
My mind is also turning over how to tie up the Adam/Aprilbot storyline and moving the Trio of Dorks onto the back burner for a while.
Basically, I know where I want everyone to end up at the end of the next story, but the logical framework to move them there is what's being turned endlessly over in my mind while I'm not sleeping at night. And before anyone suggests I get up and jot my thoughts down... it doesn't work... as soon as I crawl out of bed, I start thinking of other stuff like bills or going back to bed.
Still... progress is progress,