Ditto regarding the John Stevenson gallery and above sources. When I go gallery hopping, I usually just pick up _The Village Voice_ and see what's up. It's free anywhere in the 5 boroughs of New York or you can check online at www.villagevoice.com.
An elegant and inexpensive hotel in the "old European style" (read: bathrooms in the hallway, but it really is a nice place) in a convenient location is the Larchmont. Info at http://www.larchmonthotel.com/index.html