Place a rack in a large roasting pan. Lay a large sheet of heavy-duty aluminum foil on the rack and place the ham, fat-side up, on the foil and pull the foil up around the sides of the ham.
Pour 1 cup of the orange juice over the ham, then crimp the edges of the foil to enclose the ham and juice.
When ready to cook, start the Traeger grill on Smoke with the lid open until the fire is established (4 to 5 minutes).
Set the temperature to 300F and preheat, lid closed, for 10 to 15 minutes.
Place the roasting pan with the ham on the grill grate and roast for 1-1/2 hours. Meanwhile, make the glaze: In a small saucepan, put the remaining 1/2 cup of orange juice, the maple syrup, marmalade, mustard, vinegar, cinnamon, and cloves. Warm over low heat, whisking to combine the ingredients. Remove from the heat and reserve.
Carefully open the top of the foil on the roasting ham and generously brush all sides of the ham with the glaze. Pour any remaining glaze over the top. (Do not reclose the foil as you want the outside of the ham to caramelize.)
Increase the temperature to 400F and continue to bake the ham until the internal temperature when read on an instant-read meat thermometer is 140F and the glaze is shiny and caramelized, about 45 minutes to 1 hour longer. Let rest for 15 minutes.
Carefully remove the ham from the foil and transfer to a serving platter. Garnish with fresh orange and parsley, if desired.