View from highway- Photo - Peapack & Gladstone highway sign Pottersville Road. Junction of Morris County Roadway #512 East to community of Gladstone, New Jersey; West to Pottersville, New Jersey and Fairmount, New Jersey. This is the boro of community of Peapack, New Jersey and Gladstone, New Jersey. Pennsylvania/New Jersey Stateline to Pluckemin (Junction of Interstate Highway #78) New Jersey is a year-round destination that's never out of season. Summers are filled with boardwalk and theme park excitement and exhilarating ocean swims. Fall brings crisp autumn days that are perfect for hiking wilderness trails. Or there are lush gardens in spring and brisk winter mountain skiing.