I lived and worked in that area for a while -- there's a bunch of low-rise office complexes scattered about, especially along the I-287 corridor (Parsippany, Morristown, Bridgewater, Somerville). They're back offices for NYC-based businesses, IT departments for bigcorps (Verizon had multiple offices in that corridor when I worked for them), and lots of "professional" offices (doctors & lawyers). You'd also get the occasional interesting business -- NJ Rock Gym was in one of them at one point.