Pour juice from crushed pineapple and cranberry sauce in a measuring cup and add enough water to equal 2 cups of liquid; bring to a boil in a saucepan. Remove from heat and dissolve raspberry gelatin in the liquid. Pour gelatin into a bowl and refrigerate until partly set, about 45 minutes. Beat cream cheese with mayonnaise in a bowl with an electric mixer until fluffy; gradually beat partially set gelatin into cream cheese mixture. Gently fold 1 cup whipped topping into the mixture. Stir crushed pineapple, cranberry sauce, apple, and walnuts into gelatin mixture. Transfer to a serving bowl and refrigerate until set, about 4 hours. Serve frosted with 1/2 cup whipped topping, or as desired.