The point is Faith/Dean without polluting either timeline (AHHH, there is the rub).
Please issue comment with story. I wanna check it out. Please note that the Prison Break isn't a requirement since I didn't watch it.
REQUIREMENTS: Buffy/Gang can't know prison escapee is involved. Buffy can't meet Sam or Dean and Faith can't rat out their "Hunter"-status.
Don't involve Cas.
Write in a way that Buffy/Scoobies and Sam/Dean/Angel/Faith won't blow their respective storylines. Good Luck. Please post comment/link!