Set your grill up for indirect heat and shoot for 250 degrees.
While the grill is heating up, remove the prime rib roast from the refrigerator and allow it to come to room temp. The larger the roast, the longer it will take. This 4.5 lb roast sat out for approximately 1 hour. Season the prime rib with salt and pepper. Always use more than you think you need as some will fall off during the cooking process. This roast needed 1/2 cup of salt and 1/2 cup pepper. The seasoning helps form a great crusty bark.
Once the prime run roast is seasoned and the grill reaches 250 degrees, add a few oak or hickory wood chunks to the fire and place your meat on the grates. (Bone side down) Insert your favorite temperature probe into the middle of the roast and let cook for several hours.
Once the roast hits 100 degrees internally, start mopping with your Stubbs Moppin' Sauce. This adds a nice flavor to the salt and pepper bark that has formed during the smoking process. Baste every 15 minutes until the roast reaches 120 degrees internally. If you like your prime rib RARE, remove from the heat at 120 degrees and tent with foil. The internal temperature will continue to rise another 5-7 degrees during the resting process. If you like a medium roast, remove at 130 degrees.
Allow the prime rib to rest for at least 15 minutes so the juices redistribute. If you cut into the roast too early, those flavorful juices will run out and you will have a dry prime rib. Once rested, slice into 1 inch thick slices and serve on warm plates along with some horseradish. This will be your new favorite meal for the holidays.