park freelance study laptop

I work from home. Now that it's getting warmer out, I'd love to get my work done in the fresh air. But I can't think of any place that:

* Has reasonably comfortable benches
* Has shady spots (can't see the laptop in the sun)
* Is near a public WiFi access point
* Isn't next to noisy traffic
* Is reasonably close (15-20 minutes) to Central Square

Anyone have any ideas? I need a Starbucks-in-the-Park...