1. Combine cherries, blueberries, cranberries, ⅔ cup sugar, lemon juice, and orange zest. Mix well. Set aside for 15 minutes, stirring several times. 2. Separately, mix 2 tablespoons sugar with cornstarch. Add to fruit and mix. Set aside. 3. Preheat oven to 400°F. 4. Pour filling into bottom piecrust and smooth with spoon. Cover with top crust. Press crust rim with fork tines to crimp edge. Poke top crust several times to make steam vents. Brush top with milk. Sprinkle with remaining sugar. 5. Bake for 30 minutes. Reduce heat to 375°F, rotate pie 180 degrees, and bake for 30 to 35 minutes, or until any visible juices bubble thickly. 6. Transfer to cooling rack for at least 2 hours before serving.