Combine the walnuts, graham cracker crumbs, coconut, marshmallows, dried dates and sweetened condensed milk in a large bowl with a wooden spoon until mixture is evenly moistened. In a shallow plate, mix together the extra coconut and ground nuts. Roll heaping teaspoons into balls and roll them in the coconut/ground nut mixture. Place on parchment-lined baking sheets to dry, at least 4 to 6 hours. Store in an airtight container.