Mom always made turkey rice soup from the carcass of the roasted bird. There'd be lot of little turkey bits to pick off after simmering. She used celery, onion carrots, salt/pepper.
I like to simmer the carcass first with a peeled onion, a stalk of celery and a carrot. I fish out the carcass to let it cool so I can pick the meat off then strain the broth, add sliced carrots, celery and a chopped onion back to the strained broth (somehow, I like the fresher taste of veggies that haven't been cooked to death). Then add the rice or noodles and finish with adding the turkey bits. Season to taste.