He's talking about Stormville, NY. I can't remember if it's part of Putnam County (which I tell people is between Westchester, NY & Poughkeepsie, NY) or not. I went once when I was in HS I think.
My mom's never been, but I'm not sure if she could do it. She has severe scoliosis and needs a grocery cart to lean on for food shopping, etc and she uses a walker when she goes to the mall (basically, she can't walk/stand or sit for long periods of time, so she has to keep switching from one to another. From what I remember the Flea Market is pretty big, so it might be too much for her.