Start with an assortment of toilet tissue and paper towel rolls. Color the tubes with a coat of gold poster paint. Once they are dry, you can create the appearance of cut stone by applying a contrasting color with a small sponge square. Using a utility knife, cut windows in the tube towers (a parent's job) or just draw them on with a black marker. Cut notches around the tops of several turrets.
When assembling the castle, start from the center. Glue together two or three taller tubes for the main towers. Then, stack smaller rolls around them, interlocking the towers with tabs cut in the tube bottoms. Create the castle's front wall using a 4-inch square of construction paper. Draw on an ornate door frame and sandwich the wall between the front two rows of towers.
Now you're ready to start roofing. For each roof, cut a circle out of construction paper. Make a single snip into the center and form a cone by overlapping and gluing together the cut edges. Glue the roofs in place on top of the towers. For a miniature drawbridge, glue Popsicle-stick planks side by side onto a piece of cardboard. Attach the drawbridge to the castle wall with metallic cording or paper clip chains.