Thaw peaches, if frozen; do not drain. Preheat oven to 375 degrees F. For filling, in a very large bowl stir together granulated sugar, the 3 tablespoons flour, and 1 teaspoon cinnamon. Add peaches; toss to coat. Spread in an ungreased 3-quart rectangular baking dish. Drizzle honey over peaches; set aside.
For topping, in a large bowl stir together crushed graham crackers, brown sugar, 1/2 cup flour, rolled oats, and 1/4 teaspoon cinnamon. Using a pastry blender, cut in butter until mixture resembles coarse crumbs. Sprinkle topping evenly over the peach mixture.
Bake, uncovered, about 40 minutes or until topping is golden brown and filling is bubbly. Cool on a wire rack for 30 minutes. If desired, serve with ice cream.