Preheat the oven to 300 degrees. Place cornbread cubes on a baking sheet in a single layer. Bake until dry, about 20 minutes; set aside.
In a large saute pan over medium heat, cook sausage until it's no longer pink. Transfer to a small bowl; set aside.
Melt butter in the same saute pan. Add onion and celery, and cook over medium heat until translucent, 10 to 15 minutes. Add apples and cranberries, stir to combine, and cook 5 minutes. Add half-and-half, and cook, stirring for 3 minutes. Add sage, and remove from heat. Transfer to a large bowl. Add cornbread and sausage; stir to combine. Let cool completely before stuffing the turkey, or store in an airtight container in the refrigerator for up to 2 days.