Arrange crackers in bottom of 12x8 baking dish, cutting crackers to fit if necessary.
Microwave 15 of the caramels and 2 tbls of the milk in a small microwaveable bowl on high 1-1 1/2 minutes or until caramels are melted and mixture is smooth, stirring after 1 minute.
Spread over crackers, sprinkle with 1/3 cup of the walnuts. Refrigerate.
Pour 1 cup of milk into large bowl, add pudding mix, beat with wire whisk 1-2 minutes.
Gently stir in 1 cup of whipped topping. Spread over caramel layer.
Refrigerate at least 3 hours or until ready to serve.
Garnish with remaining Cool Whip, 1/3 cup chopped walnuts, apples and marshmallows. Microwave remaining 7 caramels and 1 tbls milk in small microwaveable bowl on high 1 minut or until caramels are melted and mixture is smooth, stirring after 30 seconds.
Drizzle over top of dessert. Store leftover dessert in refrigerator.