It was such a nice day today I got out my kayak and launched it at Langus Park.
From Langus Park you can head up the Snohomish River to the Estuary Watertrail shown in these Everett Parks and Recreation pictures and map, or you can head down the river to the Everett Waterfront and Jetty Island.
You do have to be aware of the tides and wind in this area. There are areas in the estuary that turn into mucky mud flats as the tide goes out and you wouldn't want to get stuck in your kayak waiting for the incoming tide. It's also a good idea to have a map since it's a fairly large area with a variety of interconnecting waterways (some of which are dead-ends).
If you head down river from Langus Park you get into some open water that can get pretty choppy in the wind and a little tricky with tide rips (where the outgoing river is meeting an incoming tide) and occasional boat wakes.
I generally plan my trips so I'm paddling up river on the incoming tide and reach the sloughs (Union, Steamboat and Ebey) while the tide is still rising and am out of the shallow areas before the tide starts to go out.
The estuary is a really fascinating place and a quiet kayak is a good way to explore it. I saw blue herons, cormorants, a sandpiper, some red wing blackbirds and a variety of other birds today. I've seen river otters, bald eagles, and deer on other trips into the area. It's pretty amazing considering how close it is to a densely populated area. You can read about the area in this article from the Seattle P.I.
I have an Old Town Loon 138 kayak that I bought at REI years ago which works well for the type of water you see in this area. It has a big cockpit, it's stable, tracks well, and will carry 380 pounds.