Practical range with two T-Beam devices. 7miles(11KM) Long Island area

For fun I want to establish a link between me and a friend on the long island area. The towns are about 7 miles apart… poor line of sight, relatively flat land my location is about 50feet higher then them. What kind of mods would I be looking at to make this work? I plan on using the TTGO T-Beam with an external antenna. Thanks!