Double Bluff County Park at the north end of a very long Puget Sound Fetch to the south. paddle south and downwind back north to the park, popular with kiters (October is “Double Bluff” month)
Dave Mackie Park (Maxwelton Beach) (decent amount of parking)
downwind approx. 4 miles to Sunlight Beach (very limited parking) or 4.25 miles to Double Bluff Park
Mutiny Bay - boat ramp w/ spacious gravel parking lot. On a south wind you can probably do laps, protected by the shore going upwind then turn and downwind at some angle back into the bay, rinse and repeat, kind of like using an eddy to go upstream. You might get downwind legs up to almost 2 miles but you will lose some of your upwind protection with downwind legs that go that far north in the Bay.