We will be staying at an Airbnb in the Four Corners neighborhood, on the corner of Leveroni and Broadway. The closest hotel is The Lodge at Sonoma Resort.
Cocktail, semi-formal. It does get a bit chilly once the sun goes down, so while there will be outdoor heaters, we recommend bringing a light jacket.
There will be a shuttle at the end of the night (11:30/midnight), picking up at Viansa and dropping off at Sonoma Square. There is plenty of parking at the venue if you plan to drive. You are also more than welcome to leave your car at Viansa overnight if you'd like to drive there and then use the shuttle at the end of the night.