Pamela Moller Kareman has been laughing a lot lately.That’s not to say that the director at the Schoolhouse Theater in Croton Falls isn’t taking her work seriously.It’s just that she’s working on Neil Simon’s Pulitzer Prize-winning “Lost in Yonkers,” a story that mixes heart-rending scenes of familial dysfunction with laugh-out-loud comedy.“Lost in Yonkers” comes at the end of a successful season at the Schoolhouse: from the world premiere of Todd Susman’s “Locked and Loaded,” about men making life-changing choices, to a stunning production of Arthur Miller’s “The Crucible” that transferred to Manhattan for a month-long run to “Appointment with a High-Wire Lady,” about memory, love and loss, to Neil Simon.“Lost in Yonkers” opens tonight and runs weekends through June 1 at the tiny theater in Croton Falls.Neil Simon? At the Schoolhouse?“We have discovered that this time slot for us, in the warmer, nice weather, brings in lots of interest from groups,” Kareman says.“It’s a balance that everybody has in theater,” she says. “We want to do work that we’re interested in exploring, but we also want to please the crowd. It really was a lesson we learned with ‘The Last Night of Ballyhoo’ a few years back.”“I reread it and thought it was Neil Simon at his most poignant and it’s still so funny,” she adds. “Lost in Yonkers” is about two boys, Jay and Arty, whose father goes off to look for work and leaves them with their stern grandmother in a small apartment over the family’s candy store in 1942 Yonkers.There are, of course, complications: a gangster uncle named Louie, an eccentric Aunt Gert who breathes out when she says the first half of a sentence and breathes in on the second half, and Bella, their simple-minded and sincere aunt who is a jumble of love, confusion and determination.In addition to the Pulitzer, “Lost in Yonkers” won four Tonys in 1991 — for Best Actress (Mercedes Ruehl), Featured Actor (Kevin Spacey), Featured Actress (Irene Worth) and Best Play.The story may be told by the boys, but Grandma Kurnitz is at the center of this household, a domineering voice of negativity and concern who never approved of the boys’ dead mother and made no effort to hide that fact. And she’s none too pleased to be saddled with two young boys in her apartment.But Judy Stone, who plays the role created by Irene Worth on Broadway, has a very fine line to walk, Kareman says.“She can be understandable, at least,” she says. “She may not be likable, but in some way you have to be able to understand how someone could be like this and have some kind of empathy if not sympathy for her.“I jotted something down — I jot things down on napkins — and I found this, I’m not sure where, a description about the grandmother that reads; ‘Her steely monstrousness can be found in the emotions she withholds rather than in whatever faint feelings she might grudgingly express. She shows raw anguish as opposed to emotion.’ ”Plenty to work with.Casting was difficult — “We saw a lot of people,” Kareman says — and finding young actors to play Jay and Arty was particularly hard.She struck gold when her friend, Sandy Faison, who teaches at La Guardia High School in the shadow of Lincoln Center, invited Kareman to teach a master class at the school. She met some great young actors and found La Guardia senior Gaspare di Blasi, the older brother.For the younger brother, Arty, Kareman got reams of head shots from Westchester stage mothers, “but it wasn’t happening for me,” she recalls. What she was after was the quintessential Neil Simon kid — “an old man in a little guy’s body.” She cast Cody B. Kostro, who makes his professional debut at the Schoolhouse in this show.“He’s just a hoot,” she says. “Last night, we had tech-dress and some of the crew people were seeing it for the first time and they were just roaring at the kid.”Also in the cast are: Steve Perlmutter as Uncle Louie who drove to the Schoolhouse from Manhattan and phoned Kareman to suggest that he might actually have gotten lost in Yonkers; Marilyn Matarrese as Gert, who’s getting to dress in glamorous costumes for the role, and Katonah resident Bruce Sabath as the boys’ father, Eddie. Sabath was in the recent Broadway revival of “Company.”Cheryl Orsini plays Bella, the role created by Tony-winner Ruehl. Her day job is as a waitress at Orso, the high-brow Restaurant Row eatery.“After we began rehearsal, she’s waitressing and in comes Neil Simon and casting director Jay Binder,” Kareman says. “After waiting on them, she said ‘Thank you for writing such a lovely play. I’m thrilled to be playing Bella.’ And he was very gracious and warm and sweet.“And they were on the way out and Jay Binder held back and came over to Cheryl and said ‘Don’t play her too retarded. That’s the ticket.’ ” Kareman says.Simon has described Bella as a 15-year-old girl in a 38-year-old woman’s body, with a 38-year-old woman’s desires.“And 15 is not 8,” Kareman says, emphasizing that she’s not a child, either. “And Cheryl brings an exuberance and an adolescence and struggle of who she is to the role. At one point, she asks her mother ‘Tell me who I am.What’s wrong with me? Why am I like this? Help me understand myself.’“And the mother is so cold. She says, ‘You want to know what you are? You’re a child. You’ll always be a child.’ And it’s so cruel.”But there are plenty of moments of inspired comedy, comedy that goes to character, comedy that has Kareman and her cast laughing plenty.At one point, Bella comes home and knocks on the door and Jay says ‘Guess who forgot how to open a door?’He opens the door for her and Bella says “I forgot my key.”When Jay asks how she got in the door downstairs, she says “I used my spare key.”Cue the laughter.‘Lost in Yonkers’Where: Schoolhouse Theater, 3 Owens Road, Croton Falls.When: 8 p.m. Thursdays to Saturdays and 4 p.m. Sundays through June 1.Tickets: $25 on Thursdays and Fridays; $29 on Saturdays and Sundays.Call: 914-277-8477.With: Cheryl Orsini, Judy Stone, Gaspare di Blasi, Cody B. Kostro, Steve Perlmutter, Bruce Sabath, Marilyn Matarrese.