Prepare Rosemary-Sage Stuffing : In 8-quart Dutch oven or saucepot over medium heat, in hot salad oil, cook celery and onions until tender, stirring occasionally. Remove from heat; add bread pieces, sage, rosemary, salt, water. Set aside.
Prepare Turkey : Remove giblets and neck from turkey; reserve for making gravy. Rinse turkey with running cold water and drain well.
Spoon some stuffing lightly into neck cavity. Fasten neck skin to back with skewers. With turkey breast-side up, lift wings toward neck, then fold them under back of turkey so they stay in place.
Spoon remaining stuffing into body cavity. Close by folding skin lightly over opening; skewer closed if necessary. Depending on brand of turkey, with string, tie legs and tail together, or push drumsticks under band of skin, or use stuffing clamp.
Place turkey, breast-side up, on rack in large roasting pan. Rub turkey all over with pepper and 2 teaspoons salt. Cover turkey with a loose tent of foil. Insert meat thermometer through foil into thickest part of thigh next to body, being careful that pointed end does not touch bone. Roast turkey in 325 degrees F oven about 5 hours; start checking for doneness during last hour.
While turkey is roasting, prepare giblets and neck to use in gravy: In 3-quart saucepan over high heat, heat gizzard, heart, neck, and enough water to cover to boiling. Reduce heat to low; cover and simmer 45 minutes. Add liver; cook 15 minutes longer. Drain, reserving broth. Pull meat from neck; discard bones. Coarsely chop neck meat and giblets. Cover and refrigerate meat and broth separately.
To brown turkey, remove foil during last 30 minutes of roasting time and baste with pan drippings. Turkey is done when thigh temperature on thermometer reaches 180 to 185 degrees F and drumstick feels soft when pressed with fingers protected by paper towels. (Breast temperature should be 170 to 175 degrees F, stuffing temperature 160 to 165 degrees F.)
When turkey is done, place on warm large platter; keep warm. Prepare giblet gravy: Remove rack from roasting pan. Pour drippings through sieve into 4-cup measuring cup or medium bowl. Add 1 cup giblet broth to roasting pan and stir until brown bits are loosened; pour into drippings in measuring cup. Let stand a few seconds until fat separates from meat juice. Spoon 2 tablespoons fat from drippings into 2-quart saucepan; skim and discard remaining fat. Add enough water to meat juice in cup to equal 3 cups.
Into fat in saucepan over medium heat, stir flour and 1/2 teaspoon salt; cook, stirring, until flour turns golden brown. Gradually stir in meat-juice mixture and cook over medium-high heat, stirring, until gravy boils and thickens slightly. Stir in reserved giblets and neck meat; heat through. Pour into gravy boat.
To serve, garnish platter with fresh sage, rosemary, and strawberries. Serve turkey with stuffing and gravy.