Let dough stand at room temperature for 5-10 minutes to soften. In a large bowl, combine dough and granola bars. Press into an ungreased 13-in. x 9-in. baking pan. Bake, uncovered, at 350° for 10-12 minutes or until golden brown. Sprinkle with butterscotch chips and marshmallows. Bake 3-4 minutes longer or until marshmallows begin to brown. Sprinkle with walnuts; arrange pretzels over the top. In a small saucepan, melt the peanut butter chips, corn syrup and butter; spoon over bars. In a microwave, melt chocolate chips; stir until smooth. Spread or drizzle over bars. Refrigerate for 1 hour or until firm before cutting.