Sayreville was built on clay. For more than a century the pits along the Raritan river supplied brick works that sent millions of bricks up the river and across the bay to build New York, and the town's lakes and ponds are mostly old clay pits filled with water. Later it became a gunpowder and chemical town, and later still the hometown of Jon Bon Jovi, which is the fact most visitors already know.
The town sits on the south bank of the Raritan, near where the river widens into Raritan Bay, and the Garden State Parkway crosses the water on the Driscoll Bridge, a structure with so many lanes that it has been described as one of the widest bridges in the world. Riding over it, with the river below and the refineries and towers of central New Jersey all around, gives you a good sense of the industrial muscle of this corridor.
On the swimming front, be realistic. The Raritan is tidal, muddy and busy with boats, and the old clay-pit lakes are not designated for bathing. For a proper swim, the ocean beaches of Sandy Hook, part of Gateway National Recreation Area, are about forty minutes east, with lifeguards in summer and views across the water to the Manhattan skyline.
Coming back from the Poconos, the final stretch follows I-287 or the Turnpike through the dense centre of the state, with heavy traffic, trucks and sudden slowdowns. Keep your distance and watch the merges.
Fuel is easy, and in New Jersey an attendant fills the tank for you. The diners along Route 9 and Route 35 serve everything from pancakes to Greek specials at any hour, which is a very Jersey way to close a day.