Preheat a smoker to 275°F. Add the wood pellets according to the smoker’s instructions.
Place the potatoes in a saucepan and cover them with water. Bring to a boil, then cook until fork-tender, about 15 to 20 minutes. Drain the potatoes and return them to the pan.
Mash the potatoes with the butter, warm milk, 1/2 teaspoon salt, and 1/4 teaspoon black pepper. Cover the pan to keep the potatoes warm while the meatloaf smokes.
In a bowl, mix the softened cream cheese, cheddar, and diced jalapeños. In a separate large bowl, combine the ground turkey, egg, panko, 2 tablespoons milk, kosher salt, and black pepper. Mix gently just until combined.
Press half of the turkey mixture into a compact loaf on a sheet of parchment. Spread the cream cheese mixture down the center, leaving a border around the edges. Cover with the remaining turkey mixture and seal the edges so the filling is enclosed.
Sprinkle the chopped bacon over the top and gently press it into the loaf. Transfer the loaf, still on the parchment, to the smoker. Smoke until the center reaches 165°F, about 2 to 2 1/2 hours. Check the temperature in the thickest part without touching the filling.
Let the meatloaf rest for 10 minutes before slicing. Serve with the creamy mashed potatoes.