The Lalique installation is very accessible amnd is about 25 blocks south of the Met at 712 5th Avenue, across from Trump Towers. The buiding is now the home of Henri Bendel and upscale boutique. You can enter the store and get right up to the windows, but I think they are more effective from the exterior. Below is a link to a video on a talk a recently gave o the windows. Enjoy your US trip.
Wise move to broaden your scope to seek Tiffany and LaFarge windows. I am a fuser moving into panels and there is so much to be explored yet. It is so motivating!
Vic and Mary are the best ones to formulate a list in New York. I highly recommend the The Cloisters too. It is an extension of the Met Art Museum, but a subway ride away. Well worth the day! We only spent half the day so never got to see the gardens and felt rushed.
The church in the photo is St. Mary's, a Ruthenian-Byzantine church on the corner of 2nd Avenue and 15th Street in Manhattan. (246 E 15th St, telephone - 212-677-0516).
The Met has quite a bit of stained glass on display as does the Cloisters uptown. Both are worth a visit. There is a large Chagall window at the United Nations. Other churches to see in Manhattan are Grace Church - Broadway and 9th Street and Church of the Incarnation (Madison Ave and 35th Street). If you want to visit a studio, you're quite welcome to stop by mine in Brooklyn - just let me know in advance.
VASSAR COLLEGE, in Poughkeepsie NY ( about 1.5 hrs north of manhattan) reachable by commuter railroad)has a wonderful trove of Lafarge and Tiffany windows that can be viewed up front, close and personal in their School Chapel. Also, some fabulous windows in their library too.
this link will take you to a description of some of the windows from one of vassars bulletins. If you're thinking of going there, contact the school about visiting and hrs that you might be able to view them.