Put the Chex Mix, Cheez-Its, pretzels, and Frito Twists in a large 9x13 foil pan or casserole dish (it helps if it's a deeper pan because this makes a lot).
Pour the melted butter over the snack mix and toss with your hands or a rubber spatula.
Add the ranch seasoning and all purpose seasoning blend if using. Toss until evenly combined.
Place the dish on a smoker or Traeger/ Pellet Grill set to 225 degrees for 2 hours, tossing a few more times throughout.Note: If your smoker has a Super Smoke setting, turn that on.
Let cool slightly before serving. Will stay fresh in a covered container for several days.