I think the Louise Nevelson Plaza in NYC is open to the public now. The renovations to that area were scheduled to be completed a long time ago. But I think they finally completed it all in October 2010.
Here's a link to see her sculptures still boxed in plywood just about to be reinstalled in the plaza:
She was a very ambitious female sculptor and created many great pieces that are greatly prized today my significant museums like the Guggenheim, Museums of Modern Art in several cities, the Tate, and more. If you search for history on sales of her artwork on consignment at Sotherby's or Christi's auctions, you get page after page of sculpture, drawings, jewelry, etc. that still garner very high prices.
Louise Nevelson died at the age of 88 in 1987. She spent most of her life in NYC.