I don't know for sure, but the past few years the shuttle hasn't been very dependable. The wait is usually long. Neither does it fit too many people, nor has it continued to go back and forth after the show has been going on for more than an hour or two. Meaning if you're really late, or impatient, you should probably know how to walk. It's not so bad.
The walk from the nearest train station, the Carrol Street F or G, isn't too long, about 10 minutes... and is safe enough (at least every time i've done it)... even though The Club is located in a dead factory zone located next to some housing projects... If you walk this way ( LOOK A DIAGRAM I made!!!
http://www.flickr.com/photos/16676440@N00/493328196/ )... you'll get there the quickest, and spend the least amount of time in the
scary zone... Which only happens once you cross the BQE... Which you do by walking across a ramp hereby represented on the map by a pink line floating across the BQE.
Basically, the written directions are Take the F or G train to Carrol Street. Exit at the 2nd Place, 2nd Street Exit. Take a right on to 2nd place. Walk three blocks to Henry Street and take a left. You should pass 3rd Place a public school and then 4th Place. Right after 4th place is a small dead-end called Coles Street, that isn't really a dead-end because it leads to a ramp going over the highway. Once you cross the highway and get off the ramp my memory is kind of fuzzy on exactly how you get to next street... I can't remember which way you turn off the ramp to get to Luquer Street, but its like really close. Anyway you Take Luquer street which you follow for a little while until it turns into Commerce street. You'll see The Hook in no time after that.
If anyone wants more elaboration, or knows a better way, post away.