Bring a large pot of lightly salted water to a boil; cook rotini at a boil until tender yet firm to the bite, about 8 minutes; drain.
Place bacon in a skillet over medium-high heat and cook until evenly brown. Drain and chop.
In a large bowl, mix mayonnaise, ranch dressing mix, garlic powder, and garlic pepper. Stir in milk until smooth. Place rotini, bacon, tomato, black olives and cheese in bowl and toss to coat with dressing. Cover and chill at least 1 hour in the refrigerator. Toss with additional milk if the salad seems a little dry.