Preheat your smoker to 225 degrees F for indirect cooking using a hardwood like oak or hickory for smoking.
While the grill is warming up, prepare your roast. Trim any excess fat from the top of the roast down to 1/4 inch thick. Season on all sides with an even sprinkling of salt and pepper.
In a small bowl combine the softened butter, garlic, herbs, salt, and pepper. Slather the entire roast with the butter mixture.
Place the roast on a flat rack elevated above a baking sheet, place on the smoker and close the lid. Smoke until the internal temperature of the roast reaches 120 degrees F for Rare or 128 degrees F for Medium. For a rare, bone-in roast, plan on 35 minutes per pound of prime rib.
Remove the roast to a cutting board and allow to rest for 20 minutes. Strain the butter and drippings from the baking sheet into a separate bowl and set aside.
While the roast is resting, increase the temperature of your grill to 400 degrees F.
Once the grill is up to temperature, return the roast to the grill and sear until you reach your desired internal temperature. Pull the roast off at 130 degrees F for rare, 135 for medium rare, 140 for medium. This process should go quickly, so keep an eye on your temperature.
Remove your roast to the cutting board and let the meat rest for at least 15 minutes before slicing and serving.