Sarah Swymer and her pint-sized team of inspectors are on a mission: to rate and review the city’s playgrounds by summer’s end.

In addition to running a city-tours-for-kids business and blogging under the name Sarah Poppins, Sarah Swymer is a nanny to Lexi Lee, 6, and Annie, 3. As if that weren’t enough, her alter ego, New York City Park Hopper has taken on the challenge of rating and reviewing every one of the city’s public playgrounds, partly as a creative way to keep her young charges busy. In a city with 207 playgrounds, this is no small feat.

Each park or playground gets up to five “slides” depending on, for example, how kid-accessible the swings are and whether or not there’s a water fountain, bathrooms or shade trees, as well as attributes like cleanliness and sightlines—i.e. how easy it is to keep an eye on the kids. Reviews are organized by “Highlights,” “Lowlights,” “What It’s Got,” and “What Parents/Nannies Should Know,” as well as descriptions, pictures and more. Favorites? Sarah and crew love the Courtney Calendar Park on 130th and 5th for its giant sprinklers and kid-sized picnic tables. Evelyn’s Playground at Union Square gets points for its state-of-the-art equipment (Village Voice). Says Swymer, “There’s nothing worse than dragging small children to a park only to find that it’s gross or boring.”

As for her Sarah Poppins NYC Explordinaire tours of the city’s museums, parks and landmarks, “People have loved [the tours]…because if they want to come in to Manhattan for a lunch with their friends, they have to figure out what to do with their kids.” Swymer thinks the tot-sized tours are a fun way to teach kids about New York City, and a much better child care option than TV, especially given her opinion that, “New York City is really one big playground.”