Heat giblets, water, 1 diced onion and 1 teaspoon salt to boiling in 1-quart saucepan; reduce heat once it boils. Cover and simmer about 1 hour or until giblets are tender. Strain broth; cover and refrigerate the meat and any bits of onion put aside. Remove meat from neck and finely chop with the giblets (and bits left over from broth). In a large bowl toss this giblets mixture with the toast, sage, thyme, rest of the salt, pepper, apples, celery, onion, and butter; until completely incorporated.
Heat oven to 350°F.
Fill wishbone area of goose with stuffing first. Fasten neck skin to back with skewer. Fold wings across back with tips touching. Fill body cavity lightly. (Do not pack it in the stuffing expands.) Fasten opening with skewers, and lace with string.
Pierce skin all over with fork.
Place goose, breast side down, on rack in shallow roasting pan.
If you use a meat thermometer insert it so tip is in thickest part of inside thigh muscle and do not allow it to touch bone.
Roast uncovered 3 to 3½ hours (if necessary, place tent of aluminum foil loosely over goose during last hour to prevent excessive browning/burning) if I remember I’ll spray that foil with some cooking spray so it doesn’t stick, removing excess fat from pan occasionally while it is cooking (this is a fatty bird).
Once your thermometer reads 180 degrees (F) and juice of goose is no longer pink when the thigh is cut.
The center of the stuffing should be 165 degrees (F). Your goose is cooked (funny).
Let stand 15 minutes for easier carving. Remove stuffing and crave; place carved goose & stuffing on heated platter. (This I do with all “roasts” it helps keep it warm and does not cook it) You can garnish with apple slices, cinnamon sticks, etc.
Pour drippings from pan into bowl; skim off fat.
Return ¼ cup drippings to pan
Stir in flour. Cook over medium heat, stirring constantly, until smooth and bubbly; remove from heat.
In a sauce pan add enough water and/or remaining drippings to reserved broth, to measure 2 cups.
Stir into flour & broth mixture. Heat to boiling, stirring constantly. Boil and stir 1 minute.
As you are cooking this bird breast side down you won’t have the beautiful browned look so carve this bird before bring to the table it may not look pretty but it is very moist and taste. If you like the skin browned at about a ½ hour before it is done you should try to flip the bird with oven mitts and brown in the oven. I really like this but don't be worried if it doesn't "look" pretty because you are cooking it breast down (which by the way I do with all my birds now) it doesn't look pretty but the taste sure makes up for it. Heating the platter for any type of meat/poultry is a nice touch, one of the ladies I did meal-on-wheels for taught me that trick. She said the key was not to let the platter get hot, just warm to the touch. You can also save time and draw out the drippings and prepare the gravy while the bird is still in the oven, keeping it in the pot covered will keep it nice and warm. If you do not like stuffing the bird you don't have too just adjust your cooking time (it may save 45 minutes to a half hour) you can bake the stuffing in the oven in a glass dish covered.