By Rob Lenihan A tour company offers a guide to some of the spookiest movie locations in New York City. I stood before the Greyshot Arch in New York’s Central Park with one thought bouncing around my mind: I should’ve waited until dark. Monster TownThis was the first stop of On Location Tours’ “Horror Movie Location Tour” that covers places where some top notch horror flicks were shot. Located a short distance from Columbus Circle, Greyshot Arch, which was built in 1860, was used as a shelter for two characters in the 2008 film Cloverfield, when a giant monster with a real attitude problem sto…