Set the goose on a tray. Remove any contents from the cavity, trim loose surface fat, prick the skin all over (especially where it’s thick) with a skewer or needle, and pat very dry. Rub the bird all over and inside the cavity with the kosher salt and black pepper. Refrigerate uncovered 12–24 hours to dry the skin.
Heat the oven to 425°F/220°C with a rack in the lower third. Pour the water into a large roasting pan and set a V-rack (or flat rack) in the pan.
Quarter the apples and halve the garlic; tuck the apples, garlic, thyme, sage, and bay leaves into the cavity and tie the legs loosely with kitchen twine.
Place the goose breast-side up on the rack and roast 30 minutes until the skin begins to brown. Reduce the oven to 325°F/165°C and continue roasting 2–2.5 hours, pricking the skin wherever fat pools and carefully pouring off rendered fat from the pan every 45 minutes; rotate the pan once for even browning. Roast until a thermometer in the thickest part of the thigh reads 165°F/74°C and the skin is deep brown.
Transfer the goose to a carving board, tent loosely with foil, and rest 30 minutes before carving. Reserve the rendered goose fat for cooking.
Make the gravy while the goose roasts or rests: In a medium saucepan over medium heat, brown the goose giblets and neck in 1 tbsp rendered goose fat until lightly colored, 5–7 minutes. Add chopped carrots, celery, and onion and cook until softened, 6–8 minutes. Sprinkle in the all-purpose flour and cook, stirring, 2 minutes. Pour in the dry white wine, simmer 2–3 minutes to reduce by half, then add the low-sodium chicken stock. Simmer gently 30–40 minutes, strain through a fine sieve, and skim excess fat; whisk in a spoonful of pan drippings for depth and keep warm.
Carve the goose, discarding cavity aromatics. Serve with the hot gravy.