New Yorkers Roll Up the Welcome Mat
LEAD: ASK a New Yorker, ''My place or yours?'' and the reply often will be an emphatic ''Neither.'' The excuses given for not inviting people home are legion. Lack of space, a reality of New York living, is a principal one. A highly cultivated desire for privacy, for retiring to a hideaway, is another. Logistics - you are in TriBeCa, I am at 96th and Second
