It’s Friday morning at Stinson Beach Preschool, and 13 youngsters are considering which activity to pursue once they’re released from a circle under an inflatable solar system diorama dangling from the ceiling.

Some wish to build castles with plastic blocks, others to paint or thumb through the snack spread of veggies and crackers that’s provided daily. But before they can begin, they must announce their intention to their teacher, Susan Tacherra. 

Sitting in a chair with a guitar in her arms, Ms. Tacherra reflects the classroom’s buoyant atmosphere with her long, frizzly hair and warm voice. She grants each request, and the children take off. 

“Whatever I’m doing, I’ll have music,” she said. “You can teach anything with music: language, science, math, emotional studies…” 

The classroom is stocked with games and activities that provide the preschoolers a simple, tangible introduction to larger concepts and developmental milestones. On a shelf are multiple trays for transfer games with names like “Babies in the Bath” or “Pour and Stop,” in which a child uses utensils to move tiny objects from one spot to another, practicing fine motor skills while playing. In containers of sand, children practice writing out letters through touch before committing to paper. 

The Montessori-inspired preschool that Ms. Tacherra has directed since 1996 is closing this Friday. It had rented a classroom from the Bolinas-Stinson Union School District for about a decade, but was asked to set up a portable classroom in 2014. 

Fitted with its own bathroom, the mobile classroom was required to obtain a waiver from the local water district due to its proximity to the Bolinas Lagoon. A two-year extension on the waiver is ending and, come July, the mobile classroom will be removed.

The closure is part of a transformation in early childhood education in the communities, which Ms. Tacherra said have waning populations of youngsters and families. The Bolinas-Stinson School will launch a free preschool for 4-year-olds this fall, and the area’s other preschool, the Bolinas Children’s Center, is preparing for a dip in enrollment. 

Between Stinson Beach and Bolinas, it would be illogical to have three preschools, said Ms. Tacherra, who chooses to see the silver lining. “When I think about the Montessori program closing, I think about all the ways the 4-year-olds preschool is going to help the community,” she said. 

The preschool began in 1970, co-founded by Gigi Green and Carol Wagner. It operated out of the Stinson Beach Community Center and wouldn’t convert into a Montessori-inspired program until the following decade, when Ms. Tacherra arrived. 

She was born in Paris, Tenn. in 1948 to a “pretty liberal family.” They soon moved to Jacksonville, Fla., where Ms. Tacherra immediately stood out. “I was a little alternative because I wasn’t a Baptist girl,” she said. “I have always been a little different because I was Jewish and my family read a lot and went to the opera.”

She was in 10th grade when she realized she had an inherent gift for teaching. While participating in Head Start, the early childhood education program, she noticed how easily she could seize the room and “hold the energy of a group.” 

“I found I had good group management skills. I could get them to do what I asked them to do just by willing it strongly and making it fun or engaging,” she said.

After graduating, she and a boyfriend moved to New York. They worked at the Capitol Theater in Port Chester, where she saw all the artists of the early 1970s. She said the scene left her feeling jaded. 

“I was more interested in Wilson Pickett and James Brown,” she said. “But then, there I was, in the middle of rock ‘n roll.”

In 1975, a friend of Ms. Tacherra’s sent her a map to Bolinas. Though she had never been west of the Mississippi, she soon found herself living in Stinson Beach. 

When her friend Lorelei Morris introduced her to the Montessori style of learning at a school in Mill Valley, she became hooked. She appreciated the play-based classrooms and the hands-on approach. She graduated from a Montessori training at Sonoma State University in 1978.

The following year Ms. Tacherra met her husband, Jim, at a Stinson Beach volunteer fire department ball, and they married in 1981. 

They now live on his family ranch in Bolinas, where they sell beef, a crop of grass-fed calves each year, as well as eggs from chickens and ducks. 

When Ms. Tacherra began working for the Stinson Beach Preschool in 1976, she helped establish it as a nonprofit, but would leave in 1983 to start a new program with Ms. Morris, called Creekside Montessori, in Bolinas. The school ran for nine years, serving a community that was then flourishing with children.

One of the youngsters in Ms. Tacherra’s class was Omar Rifkin. He vividly recalls walking in on his first day and joining his peers as they learned the alphabet by singing the sound of each letter.

“I just remember that she was very bubbly, charismatic and gentle,” said Mr. Rifkin, who has worked for Ms. Tacherra as a teacher’s assistant for the last 11 years. “From the moment I got there, she invited me in and created a comfortable safe space. I’ve taken that from her: creating an environment where children are comfortable with learning and dealing with problems. If you’re too rigid, children can’t open and you’ll only see certain aspects of the child.”

In 1996, the director of the Stinson Beach Preschool departed, and Ms. Tacherra was asked to return. She spearheaded a relocation from the community center to a classroom on the school district’s campus. She managed the program as a co-op, getting help from parents in grant writing, fundraising and coordinating fieldtrips.

Two of Christine Cunha’s children attended the preschool over the past decade, and she has both served as treasurer and worked as its bookkeeper. Ms. Cunha called Ms. Tacherra “a pillar of our community,” training her and other parents to work together and be effective board members.

“It was definitely a collaborative effort that has made that school run for the 40-plus years it’s existed,” she said.

Ms. Tacherra spent the last few years searching for a new space for her program (“I turned over every rock–twice!” she said) but was unable to find a fit. She’s considering her options for what to do next, including helping a friend create an equipment catalog for teachers and working as a consultant and mentor. Mr. Rifkin, who said early childhood education is his life’s work, is applying for teaching positions over the hill.

As the Stinson Beach Preschool approaches its sunset, Ms. Cunha feels its absence will create a gap in the community for early childcare that only Ms. Tacherra could fill.

“The thing about preschools is a lot of it revolves around the philosophy of the director,” she said. “Susan really just has a way with the kids. That’s the part that I think will be hard to replace.”