I plan to arrive at 1pm. I plan to leave at 7pm.

If we have a group arriving later, I'll try to add a trip to the dock to pick-up. 

4056 W Lake Sammamish Parkway SE, Bellevue.

You can drop-off stuff down the driveway but DO NOT park in the driveway. Park on the street or across the street in the '41.5' neighborhood.
Don't knock on the door & bother the old people. Just walk around the house to the lake.

Bring a cup with a lid if you don't want a 'marginal' sippy cup.
I have a giant cooler, life vests, floaties, inflator and a lily pad.