I would get a PATH Smartlink card, pay the $5, which then lets you buy rides in increments of ten, 10 for $26, 20 for $52... For the subway, get the unlimited weekly card ( $33, I think, after 12 rides it pays for itself.. get one for each person..)

As to staying near either Exchange Place or Newport in JC, do not forget to take in at least one sunrise and one sunset.. you'll thank me later ;-)