Take part in the harvest at some of the dozens of "pick your own" farms and orchards in the Highlands. The farthest south in the area, 250-year-old Riamede Farm (open daily, 9:30 a.m. to 4 p.m.) offers up to 30 varieties of apples as well as pumpkins (starting September 28), plus free hay rides on weekends. Call ahead to ask about opening hours at Windy Brow Farm (359 Ridge Rd., Newton; 973-579-9657), which offers seasonal fruit and vegetable picking year-round; aim for mid-September to coincide with its apple-centric fall festival. The Beemerville Orchard (73 Lusscroft Rd., Sussex; 973-875-1029) is a family-run operation where you can pick apples and drink homemade cider on Fridays and Saturdays, but for cider doughnuts you'll need to go to Pochuck Valley Farm (open daily, 9 a.m. to 4 p.m.), where you can also hand-pick winter squash, zucchini, pumpkins, and gourds.
Let the farmers do the work for you by skipping the picking and heading straight for the roadside farm stands. In addition to seasonal produce, the Farmer’s Wife (383 Rt. 519; 973-702-7614) sells a locally popular mix of jams including standard flavors as well as lemon-blueberry and white cranberry. Peach lovers, meanwhile, should go to Brook Hollow Farm (Rt. 94 Frog Pond Rd.; 908-496-4577). And if you're looking for ideas for utilizing your apples, look no further than the Ralston Cider Mill ($5 admission) for inspiration. The 150-year-old working cider mill offers tours as well as step-by-step demonstrations on making the fall favorite.
Take in the stunning foliage on horseback at the Spring Valley Equestrian Center ($40 per hour; call ahead to reserve) in Newton, which has more than 30 miles of trails for beginning and experienced riders. If you prefer to stay on foot, the New Jersey Botanical Garden is an ideal place to see nature uninterrupted, including the hundreds of species of birds and butterflies that pass through during their seasonal migration.