For all its popularity and spectacular shoreline, Montauk has inadequate beach parking. This is most acutely the case at Ditch Plain, which is both a well-known surf mecca and a sunbathers’ favorite. Parking there seemed almost an afterthought until recently, when East Hampton Town undertook small-scale expansions at so-called Dirt Lot and Otis Road, and the reconfiguration of the main lot closest to the lifeguards.