Place the red potatoes in a large pot and cover them with water. Set the pot over high heat and bring the water to a boil. Reduce the heat to medium and let the potatoes simmer for about 15 minutes, or until they are tender when pierced with a fork. Drain the potatoes well and allow them to cool.
In a large mixing bowl, combine the sour cream, mayonnaise, and Ranch seasoning mix. Stir the mixture until it is smooth and well blended.
Add the cooled potatoes to the bowl with the ranch mixture. Sprinkle in the shredded cheddar cheese and sliced green onions. Stir everything together until the potatoes are evenly coated with the dressing and the cheese and onions are well distributed.
Top the potato salad with the crumbled bacon, distributing it evenly over the surface. Cover the bowl with plastic wrap and refrigerate the potato salad until it is chilled and ready to serve.