Located in the Bellevue/Kirkland area, Bridle Trails State Park is big: almost 500 acres and with 28 miles of horse and hiking trails. State parks have taken a major hit financially in recent years, and a local group, the Bridle Trails Foundation, was established by some local interested citizens to help maintain this area as a public space.
As a bonus, the group puts on a lot of community activities. My very first mushroom walk in 2009 was a free one they offered, and then in July of 2011, I headed back for this free nature photography class taught by Andy Held. The class was helpful to me, as even after having my DSLR for a over a year, as I had by this point, I was still really rusty from my years away from photography. Also Jim Erckmann, who had taught my mushroom class and often leads the park nature/botany walks, was there to help me identify some plants that were new-to-me at the time. A twofer. Preview gallery below and full gallery with captions here.
Check out the Bridle Trails Foundation site for their upcoming events. In August, they have a presentation on coyotes (with free hot dogs!) and a botany walk. Also keep an eye out for the fall mushroom walks. I will admit I went to a second one with a different teacher that was not as good as the 2009 one listed above, BUT it's free and so as a starting point, I think it's still worth it.