The Monroe that I know of in NY is upstate, just west of Bear Mountain, near Sugar Loaf.
The RJ Monroe is fictional, I do believe, but located on LI, in Nassau County, where you can take the Glen Cove exit off the LIE (Long Island Expressway) and head north to the Sound. Wander a few back roads and you'll find Monroe (if you dare!).
The areas around Monroe, and in Shoreham and the Hamptons that FPW has referenced in various RJ novels are real. They do exist. For instance, he mentioned Randall Road as the place where Melanie purchases land to dig for the items left behind by Tesla after his experiments. Randall Road exists; I learned to drive on Randall Road.
The Pine Barrens in New Jersey most definitely exist. The best episode of the Sopranos takes place there, too!
Reading is freedom.
The mind soars, no earthly cares,
no limitations.
A Maggers Haiku, 2005
Years ago my mother used to say to me... "In this world, Elwood, you can be oh so smart or oh so pleasant."
Well, for years I was smart.
I recommend pleasant.
You may quote me.
Elwood P. Dowd