The highpoint of New Jersey is in the High Point State Park in the far North-West corner of the state, just a few miles from Port Jervis, NY. It's an easy drive from New York City, but it's just far enough out that as you get within 30 miles or so of the park, the slums have given way to suburbs and the suburbs have given way to rolling hills with pretty fields, farms and forests.
I arrived at the end of September and the road was lined with farmer's stands selling pumpkins and chrysanthemums; the weather was a perfect warm autumnal afternoon and the view from New Jersey's highest point was lovely. Hawks soared in the sky over the valley and the leaves were just showing a hint of color.
The park entrance is on the right of Rt 23 North, and a paved road leads from the entrance all the way up to the 200-foot mini-Washington Monument with parking at the foot.
Directions to High Point, NJ from the the NYC area (east/south)
From the South: Take I-287 to Rt 23 North
From the GW Bridge: Take I-80 West to Rt 23 North
Follow Rt 23 North High Point State Park
~ 7 miles north of Sussex, NJ
~ 3 miles north of Colesville, NJ
The road goes directly up to the monument at the summit with parking just below