Set the pork on a flat rack in a shallow roasting pan. Cover the end of each bone with a small piece of foil.

Make the marinade: Bring the apple cider to a boil over high heat and reduce by half. Remove from the heat, and whisk in the vinegar, mustard, brown sugar, garlic, thyme, and salt and pepper. Slowly whisk in the oil.

Using a pastry brush, apply the marinade to the roast, coating all surfaces. Cover it with plastic wrap and allow it to sit until the meat comes to room temperature, about 1 hour. (Or you can brush the marinade on the roast and return it, covered, to the refrigerator until ready to cook. Let the meat warm to room temperature before putting it on the grill.)

When ready to cook, set grill temperature to High and preheat, lid closed for 15 minutes.

Arrange the roasting pan with the pork on the grill grate. Roast for 30 minutes.

Reduce the heat to 325℉. Loosely fill the crown with the stuffing, mounding it at the top. Cover the stuffing with foil. (Alternatively, you can bake the stuffing in a separate pan alongside the roast.)

Roast the pork for another 1-1/2 hours. Remove the foil from the stuffing and continue to roast until the internal temperature of the meat is 150℉, about 30 minutes to an hour. Make sure the temperature probe doesn't touch bone or you will get a false reading.

Remove roast from grill and allow to rest for 15 minutes. Remove the foil covering the bones, but leave the butcher's string on the roast until ready to carve. Transfer to a warm platter.

To serve, carve between the bones. Enjoy!