Put the potatoes and the chicken thighs in a large pot. Cover with salted water and boil, skimming and discarding any scum that rises, for about 25 minutes or until the potatoes are soft and the chicken thighs are cooked through. Drain and set aside.
In the meantime, light the fire using hardwood charcoal. Place the corn in a large bowl of water and soak thoroughly, about 20 to 30 minutes.
When the coals are red in the center with ash around them, the fire is ready. Put the lobsters and corn on the rotisserie grill. Arrange the potatoes, chicken, and sausage on top of the grill and top with the clams. Cook for 45 minutes. Serve with melted butter.