A rental car would be highly encouraged. You could Uber, but it is likely that the cost of your round-trip Uber fare to and from the airport will be at least greater than or equal to the total cost of a rental car. Unfortunately, because guests will be staying in various locations, we will not have a shuttle transport between events or between venue and hotel(s).
Hopefully we will see more sun than rain in the summer. That, said, PNW weather can greatly vary. Layers or having some form of layering available would be recommended, particularly if rain is in the forecast. A shoe that can be comfortable enough to walk in/on a loose gravelly beach is also recommended. And a shoe that can comfortably and effectively cut a rug-is recommended for the reception!