APTOS -- Imagine a school play structure filled with shrieking, laughing children, climbing ladders, zipping down slides, swinging from bars.

Now picture a kid in a wheelchair, or one who uses crutches or a walker to get around.

Think of Madelyn Cline, a petite 5-year-old with blue eyes behind round lavender glasses. The Valencia Elementary School kindergartner has Rett syndrome, a neurological impairment that affects her balance and mostly sidelines her at recess.

But that will soon change. Valencia, home to a special class for children with moderate to severe disabilities, is replacing an aging play structure with one that will provide access to all children. The first of its kind in Northern California, the new Boundless Playground could be installed by the time Madelyn enters first grade in August if the last few thousand dollars is raised in time.

"Having a Boundless Playground will mean that Madelyn will be able to play alongside her friends, her schoolmates or her brother without visible difference," said Deardra Cline, Madelyn's mother. "She can move about the play structure like a typical child can. She can freely explore her environment."

Since the 1997 founding of the National Center for Boundless Playgrounds, a Connecticut-based nonprofit, more than 100 of the specially designed play structures have been installed around the country. The three in California are clustered near Los Angeles.

The nonprofit advocates for accessible playgrounds and certifies the structures meet certain standards. The equipment is manufactured and installed by industry partners.

Valencia's playground will have the traditional ladders, poles and steps to access the various levels, but also will include ramps and ground-level activities. The traditional ground cover of wood chips, which supply a soft place for landings but are difficult or impossible to navigate by children in wheelchairs or with balance problems, will be replaced by a rubbery mat.

"We hope it will be role model for many other communities," Cline said. "It will be a jewel for our community."

Cline brought up the idea of building the Boundless Playground at Valencia last year after a fitness structure, not easily accessible by children with disabilities, was installed with the help of the Home and School club. Since then, the club has raised $63,000, and purchased the Boundless Playground structure. Grants have supplied another $41,000, but the school is still $15,000 to $25,000 shy of covering the installation costs and looking for help.

Installation is more expensive than a traditional playground because of the special ground cover.

Completing the Valencia project could be just the start. Susan Ramos, an occupational therapist for Pajaro Valley schools, said she's been impressed with the equipment and plans to work to get a Boundless Playground at a Watsonville park. The playgrounds not only give disabled children the chance at physical activity and to socialize, they provide the opportunity for disabled parents and caregivers to play with their children, she said.

"They're really inviting, appealing to all kids," Ramos said.