Lightly trafficked paths to walk reactive dog on?

Hi, I am looking for recommendations for very lightly trafficked walking paths/trails around Dutchess/Putnam/Westchester to take my dog on. He is an 80lb German Shepard is reactive to both people and dogs (not necessarily aggressive, but will bark loudly/lunge), so I would love to find somewhere we will not come across many or any people. He loves to go on walks but they can be very stressful for both him and myself.