Navigating Manhattan for Idiots (a question)

Please keep in mind that I've not been "Back East" in about 16 years. At worst I've had to navigate Phoenix, which is frustrating, but not horrible. It took a coworker to remind me that driving won't work in this case.

I will need to get from the WTC subway station to the Broad Street Ballroom at 41 Broad Street. Should I walk, or is there a quicker way to navigate the subways? Walk from the WTC station to the Fulton St. station and take the J or Z line down to the Broad St. station (which is really close to the final destination)? What'll get me there quickest? I have Lower Manhattan and Regional Transit maps, but I'm not sure I'm interpreting them correctly, which is why I'm looking for help.

I have to be at the ballroom around 1pm, and there's no limit to how early I can start. I'll be starting from Penn Station in Newark and taking the PATH Rail to the WTC station, but that part is easy (assuming I find the correct exit off the Parkway).

I've spent the last 5 years in a town with one blinking red traffic light, and some stop signs. Santa Fe, Albuquerque, Tucson and El Paso are easy, but I'm used to driving everywhere. I've not had to navigate a metro line in a LONG time!