Not hemlock. China gave us the wooly adelgid and they are tearing up hemlocks here. Lots of hemlock skeletons in Pennsylvania.One could plant a line of fast growing trees and shrubs along that property line, thus blocking that lane and the neighbor's view. A mix of hemlock, Osage orange (the thorns make it an effective traditional barrier), maybe some transplanted beech saplings, nice prickly blue spruce, whatever will grow thick (close together, not necessarily trunk size) and quick, in that area.