Central New Jersey is not where anyone goes looking for mountain roads, and Dayton, part of South Brunswick township, makes no pretence otherwise. It sits in the flat country between New Brunswick and Princeton, crossed by Route 130, the New Jersey Turnpike and US 1, with warehouses, office parks, farms that have survived development and a lot of commuters. Think of this as a place to regroup on the way to the good stuff rather than a destination in itself.
That said, a little local knowledge makes the area surprisingly pleasant. Head west towards Kingston and Princeton and you meet the Delaware and Raritan Canal, dug in the 1830s to move coal between Philadelphia and New York, now a long, tree-shaded park with a towpath and old lock-tender houses. The back roads around it are flat but leafy, especially in autumn. Princeton itself has the university, a famous Revolutionary War battlefield from January 1777, and plenty of cafés along Nassau Street.
From here the routes that make the trip worthwhile point north-west, towards the Sourland Mountain ridge and eventually the Delaware Water Gap, or north towards the Hudson Highlands. Expect traffic signals, aggressive commuter driving at peak hours and some rough patched asphalt; summer brings heat and humidity that make an early start very sensible.
The practical side is easy. Fuel stations are everywhere along the main highways, and New Jersey still does not allow drivers to pump their own fuel, so you wait for an attendant, which is either charming or maddening depending on your mood. Diners, delis and chain coffee shops are never far away. Take the break here, check the route, and save your energy for the hills further on.