Re the chucking plates around thing - I seemed to have cured ds of this. My methods might not be to your liking though - every time he did it I shouted NO!, wagged my finger 2 inches from his face and gurned at him with a brow knotted frown. It seems to have done the trick!
Re how much going out is done with ds - well he joins in with everything dd does. When at home with them (4 days a week) we have at least one outing per day varying from the relatively simple (walks, trip to the shops, friends houses) to the more involved (trip to the zoo where we are season ticket holders etc)