I think the Supernatural plot is great. I starting watching in Season 2 when the colt first started making an appearance and always wondered about the back story of the gun and the situation it arose from.
The series is great for adventures. I know you are using Deadlands. I see they have an RPG that just came out for Supernatural and wondered if the game was any good. I know the Serentity game was a bomb and wondered if the RPG was Supernatural was any good.