Well what if the bomb was not located in a metropolitan area (just like most of the Zodiacs chosen kill sites), but still in the Zodiacs killing field? An area where he could setup a bomb on the side of a road with very little interruptions. What if his intended target(s) were not school children rather "blue meanies" (booby trap) who would have went to the bomb site if the cipher was solved? We are of course left with a lot of "what ifs" without getting the full story from the Zodiac, but he did give us a few clues in his letters.
In my opinion along with Dave C the Z32 has to give you a latitude and a longitude of where the bomb is. How else does one give you directions to a pin point location in such a short code? If it was standard directions (turn left her, turn right there…) the cipher would have to be much longer. Just trying to think logically here. There are theories out there that the Zodiac had some military training. How would someone in the military tell you exactly where a location is in the shorties format?
Check out this website when you get a chance. ZodiacZ32.com.
The author Dave C translates the Z32 into something like this: