May I suggest a new venue for kayaking and beverages? Lake Washington ends in Renton by the gorgeous Gene Coulon Park. The Landing is minutes away with lots of eating options and a movie theater. Here's my thoughts...
Gather at the Cascade Kayak Center at the southern tip of Lake Washington. Center opens at 11:00, so that would be a great time to drop the kayaks in. They do take reservations, but not required.
Drinks and food after on the patio at Vino at the Landing wine bar, a few minutes away in The Landing between Boeing and Fryes.
Here's the website for the Renton kayak center:
You really should call and reserve yourself a kayak. They are surprisingly well stocked at this location, but better to be safe than sorry. Reasonable rates and a vast selection of kayaks at this location.