Moominpappa at Sea, Paperback/Tove Jansson

Moominpappa is feeling at a loss. He has no idea what to do with himself - it seems everything has already been done! So he takes his family off to start a new life in a lighthouse on a tiny, rocky island far out to sea. It's rather lonely at first, but it isn't long before the Moomins discover some funny and surprising new things about themselves.