In a large bowl, combine sugar, flour, cinnamon and allspice. Add peaches and blueberries; toss to coat.
Preheat oven to 400°. On a lightly floured surface, roll half of dough to a ⅛-in.-thick circle; transfer to a 9-in. pie plate. Trim even with rim. Add filling; dot with butter.
Roll remaining dough to a ⅛-in.-thick circle; cut into ½-in.-wide strips. Arrange over filling in a lattice pattern. Trim and seal strips to edge of bottom crust; flute edge. Brush lattice strips with milk; sprinkle with cinnamon sugar.
Bake until crust is golden brown and filling is bubbly, 40-45 minutes. Cool on a wire rack.
