Hello Goose, you say you are nostalgic for a picnic. I too love picnics but you can still do them on a lesser scale than the olden days when it included sitting on the ground on a pretty table cloth. Nowadays mine comprise an apple (all chopped up and ready to eat), a sarnie of my choosing, a small piece of cake or biscuit and that's it.
So many places offer take away tea or coffee you don't even need to take a flask with you. If you live near a Waitrose if you get one of their My Waitrose cards you can get a FREE coffee every day.
Places to eat this said picnic range from a park bench, in the car, on the bus, or even in your own garden. Enjoy.