Bring root beer and sugar to a boil in heavy medium saucepan over high heat. Reduce heat to low and simmer for 45 minutes or until mixture has reduce by 3/4 and is syrupy. Remove from heat and allow sauce to cool to room temperature.
Place the root beer candies in a plastic re-sealable freezer bag. Lay the bag flat on a hard surface and cover with a hand towel. Using a meat mallet or hammer crush the candies to a course consistency.
Scoop ice cream into 4 sundae dishes. Spoon 1/4 cup of the root beer sauce over each dish of ice cream. Top the each sundae with a heaping dollop of whipped topping. Sprinkle with sugar cone chips and crushed root beer candies. Place a cherry on top and serve immediately.