Preheat the oven to 400 degrees F. Prepare a grill for medium heat.
Prick the potatoes with a fork and bake until cooked through and tender, 1 hour. Scoop the flesh into a bowl, leaving the skins intact. To the bowl, add some salt and pepper, the cream cheese and Monterey Jack, and the garlic powder. Mix until well blended, then spoon into the potato shells. Sprinkle with smoked paprika.
Place the stuffed potatoes on the grill and cook for 10 minutes. Serve topped with bacon and scallions.