Spencer Island provides a wonderful range of walking options, up to several miles, in the shadow of the freeway and sewage treatment plant. It is a large restored wetland in the Snohomish River delta just north of Everett. The south end is a wildlife preserve (no dogs allowed here), but hunting (waterfowl) is allowed on the northern part. To get to the island you have to walk under the freeway and past the sewage treatment plant. But once there, one forgets about those unpleasantries while watching bald eagles, osprey, great blue herons, ducks, gulls, and countless other birds. Once I watched a weasel carrying a mouse to its young across one of the many foot-bridges between the dikes.
You can see picturesque boats (sadly, some are abandoned "derelict" vessels polluting the waters) on the river also. It's a great place to go when you want to soak up the sunshine and don't feel like hiking in the deep, dark forest. For a longer walk, park at nearby Langus Riverfront Park, where you may see rowing teams in their shells practicing on the Snohomish. (Note: there is a paved trail to the island, but once then it is "hog fuel" (basically sawdust) surfaces, so you would likely need a specialized wheelchair to move about the island.
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