Bring the prime rib roast to room temperature, about 2 hours.
Rub olive oil and seasoning into the roast on all sides.
Heat the coals on one side of the charcoal grill. When hot, sear the roast on all sides above the charcoal, then move it to the other side for indirect heat.
Keep the coals burning, adding charcoal as needed and mesquite for an extra layer of flavour.
Cover and let smoke/roast for about 2 hours until it reaches 125–130 °F for medium-rare. Ralph doesn’t use a thermometer; he can “feel” when it’s done.