There was a question on at least one other board asking what sorts of Italian communities there were in New Jersey. The poster had hoped that there might be another Arthur Avenue somewhere. I'm moving the answer over here so it can get input from those who know best.
I'll kick this off by mentioning a few places. The biggest Italian neighborhood I've yet found in New Jersey is Chambersburg in Trenton. In no way is it worth a trip from Manhattan, but if you're in the Garden State, this is the place to go.
In true suburban style, Chambersburg doesn't really offer a place for strolling in the sense that Arthur Avenue does, but like I say, if you've driven, you'll have no trouble parking.
This area is famous for its Tomato Pies, a genre of pizza often discussed here, but it also has a few terrific shops and bakeries. Porfirio's Italian Food at
320 Anderson Street, Trenton, NJ 08611, 609.393.4116 is my own favorite. If you seek a clean, friendly source for high-quality Italian products, this is your spot.
Chambersburg also seems to have a thriving fine dining scene, but I've never experienced it. I always wind up blowing my money on groceries and tomato pies.
I hope this helps.