For a south to north downwind, look for a south wind on an ebb tide (ebb current goes south). Rumors have it conditions may be similar to the Columbia Gorge. There is an easy put-in and take-out.
West Side
Camano Island State Park to Madrona Beach (Saratoga Passage) ~ 7.5 miles
If you want to spend more time here there are cabins in the park, right on the beach that rent for $63 per night in the off season, and include heat, fridge, microwave and 2 double beds. Some cabins are pet friendly.
Continuing on to Maple Grove Boat Launch would add 4 miles to this run