I grew up in Central Jersey and some of the systems includes Somerset Med Ctr based on Somerville, Hunterdon MC in Flemington with satellite offices in the Hunterdon county / west central area, and the biggie is Robert Wood Johnson / UMDNJ which is based in New Brunswick (VERY convenient to hop on the train to get your city fix). RWJ has also taken over the operations of some of the smaller hospitals in the area. I know there's a system up in the Morris county area (St. Barnabus?) but I've been out of Jersey for 6 years but go back about once or twice to see the fam in central Jersey. Hope this at least gives you some systems to look into.