D & R canal path between New Brunswick and BoundBrook took a big hit with the Spring flood. Parts of the surface real rough and still being repaired. If you keep heading towards Princeton, jump off the tow path at Amwell road, cross the canal to canal road and continue on. Canal Road is a great bike route. For variation, once in Rock Hill, turn right and climb up the hill and come back to Amwell on River Road. Nice rolling hills.