Brine the turkey for 12 to 24 hours in your favorite store bought or homemade brine. After brining, rinse, pat dry and rub the turkey down with you favorite poultry rub.
Place the turkey in a 250°F smoker with a combination of hickory and apple wood chips. Smoke the turkey until the internal temperature reaches 170-180°F. After the turkey has cooled, debone and save the carcass.
Place the turkey carcass in a large pot with 8 cups of water, 2 coarsely chopped celery stalks, 1 coarsely chopped medium onion, 4 minced garlic cloves. Boil for 1 hour, strain and save broth.
In a large heavy pot or Dutch oven, over medium heat, combine the oil and flour. Stirring slowly and constantly for 20-25 minutes until a dark roux is formed. Add the chopped onions, bell peppers, chopped celery and chopped garlic. Stir for 8-10 minutes until the vegetables are soft. Add the thyme and cayenne while continuing to stir. Add the reserved smoked turkey broth and stir until the roux mixture and broth are combined. Bring to a boil, then reduce the heat to medium-low and cook uncovered, stirring occasionally for 1 1/2 hours. More water may be added if the sauce gets too thick.
Coarsely chop the smoked turkey meat. Add the turkey and the sausage to the gumbo. Cook for 15-30 minutes. Add salt and pepper to taste. Remove from heat and let sit for 5 minutes before skimming off the fat that has risen to the surface.
Serve the gumbo in individual soup or gumbo bowls over hot white rice and garnish with green onions and parsley.