I like the little day bed and the window and beat board walls. day bed on plywood base with built in table. we would put the long edge further back for under the bed storage space. I also would want to paint it like white or something.
Simple built-in to create a mudroom and/or storage anywhere from an entry, to kids room or in a laundry room by adding shelves or a deeper bench for sitting. Put drawers under bench or have the seat lift up to store things.