Ed, it seems to me I've seen plenty of subordinate or interrogative expressions that end in "bound" without "for," but this lyric is the example that leaps to the top of the list:
Can't help but wonder where I'm bound.
Adding: a search on "Which way are you bound" turns up a number of archaic hits. Perhaps this direction-rather-than-destination usage feels strange because it has become uncommon in current speech and writing.