Mag Chalkboard Paint: Paint a wall, have some craft activities to have her make castle/house/outdoors/etc pieces (modular ideas so she can build the castle in many different configurations). Also could use chalk to outline and draw.
DIY: Framed Chalkboard Wall Tutorial - this shows how to construct the frame + how to prep & paint the wall with chalkboard paint. The painted wall concept would also work if you have an unused frame. Put this between 2 doors in the basement hallway