I also did some outstanding climbs in north California recently. Don't worry, there's very worthwhile climbing in range of New York City too -- not as big, but plenty interesting.

For a single climb, Bear Mountain fits that request, with interesting curves and variations in steepness -- and can make it longer, over 4 miles if start at rt 9W down by the river. (All a little less than an hour's drive from the GWB, according to google maps).Epic sequences of hills are where the NYC area beats out northern California.

North New Jersey around Vernon has this great sequence of steep climbs - (much much steeper than the requested 6%, need to be able to handle going up and down short 22% sections). Just barely more than an hours drive from the GWB, according to google maps. For those who do not bring either very low gears or very strong legs, this sequence could result in thrashed muscles, falling over, or outrage that anyone suggested trying it.

For those who can handle driving as much as an hour-and-a-half, there are even longer seqences of interesting steep hills in rather pretty farm country out in western NJ -- but again that's not for riders looking for moderate steepness around 6% grade.I've also done most of the big famous "epic" climbs in Europe -- but really I find that the sequences of shorter climbs around are more fun.

Ken