That means a 20-pound turkey will take four days to thaw out. So plan ahead. Wash the turkey with cold water. Don't forget to remove the paper-wrapped gizzards, neck, etc. Never buy a raw, prestuffed turkey.
Most turkeys come with cooking instructions, and recipes are available in almost any cookbook.
Don't try to be creative, especially with cooking time and oven temperature. Follow the recipe. If the ingredients in your stuffing recipe normally require refrigeration, make the stuffing when you are ready to stuff the bird. Don't let the stuffing sit on the counter. Don't make it the night before and refrigerate it, because as it cooks the cold stuffing will reach room temperature and remain at that temperature long enough for bacteria to grow.