I'd recommend mine, but I can't. Don't hurt your brain with them, no good can come of reading them. I would recommed:
Ronman The Barbarain (Amusing, fun...might not be yours since its a fusion, but too good not to recommend)
and any of the Kim Possible Fics by
Mattk.
However, with him to not get confused, read the following in this order:
Thunderheads on the Horizon
Bleeding Out
Bleeding Through
The others are side stories (or only loosely related) and not critical to really enjoying the story. Also of note, these are all set pre-season 4, shortly after 'So The Drama' movie.