Among the best picnics, adult or otherwise, A Picnic in the Woods sets an example of optimistic picnic fun. It begins with the usual refrain: “It’s a beautiful day for a picnic!” as Mickey Mouse, Minnie Mouse, and Mickey’s nephews Ferdy and Morty cram into the blue convertible for a day in the country. 
Soon, they arrive at a park picnic area with a table with benches, a fireplace, and a covered seating shelter.
They cook food, play games, fight mosquitos, escape the rain, and at last, happy and satisfied, they drive home top down in the blue convertible, of course.
See Walt Disney Productions. A Picnic in the Woods. New York: Random House, 1983.