I moved to plainsboro last spring, and let me tell you that you are in luck - the trails, roads, and paths around here are an omnivorous cycling delight.
The main problem with riding as a newb out here is that it can be difficult to stick the back roads without either being overwhelmed by route changes every 2 miles or getting stuck on the shoulder of a major highway. The CR's can go from perfect biking to narrow speeding-car traps to highways all in a couple miles.
Have you looked into the Princeton Freewheelers? Its not my thing personally, but they stretch down into PA & have a good local knowledge base.
I would recommend cutting over to Ocean Grove (when I find a good alternative to 33 I'll let you know, this is my next 'big trip' idea) - its a very bikeable town, only 30-40 miles away, and your already on the coast.
I would also recommend using the D&R canal - its a great way to get north, south, and into PA while sticking near bike-friendly roads.
The problem with the AC/Ocean City area is that it seems to be either heavily trafficked urban roads or highways. Sandy-hook, though, has alot of local bikers and local routes.