Cook 12 ounces pasta according to package directions until al dente. Drain well and rinse under cold water to stop cooking. Let drain completely.
Cook 6 slices bacon until crisp. Let cool, then crumble into small pieces. Dice 8 ounces turkey into bite-sized chunks.
In a large mixing bowl, combine cooled pasta, diced turkey, crumbled bacon, 1 cup halved tomatoes, 2 cups chopped lettuce, 1 cup cheese, and 3 sliced green onions.
In a small bowl, whisk together 3/4 cup mayo, 1/4 cup ranch dressing, 1 tablespoon ranch seasoning, 1/2 teaspoon garlic powder, and 1/4 teaspoon pepper until smooth.
Pour dressing over pasta mixture and toss gently until everything is evenly coated. Taste and adjust salt if needed.
Cover and refrigerate for at least 2 hours before serving to allow flavors to meld. Stir well before serving and add extra dressing if needed.
