Place the turkey carcass and water in a Dutch oven or soup kettle; slowly bring to a boil over low heat. Cover and simmer for 1-1/2 hours.
Remove carcass and discard. Strain broth through a cheesecloth-lined colander. If using immediately, skim fat or refrigerate for 8 hours or overnight; remove fat from surface. Stock may be refrigerated for up to 3 days or frozen for 4 to 6 months.
For soup, return strained broth to pan. Add the turkey, vegetables, rice, bouillon and seasonings; bring to a boil. Reduce heat; cover and simmer for 30 minutes or until rice and vegetables are tender.
Turkey Barley Soup: Prepare stock as directed. For soup, omit stewed tomatoes and rice. Bring stock to a boil; add 1 cup uncooked medium pearl barley. Reduce heat; cover and simmer for 30 minutes. Add remaining ingredients. Cook, uncovered, for 20-25 minutes or until barley and vegetables are tender.