To roast the chicken, rub it with salt, pepper and olive oil and bake at 400° until it reaches an internal temp of 165°. Allow the chicken to cool just enough to handle, then debone and chop. (Discard the skin).
While the chicken is still warm, add the vegetables and cranberries.
Dump the mayonnaise right on top of the chicken and sprinkle it with the garlic powder and mustard. Swirl it around to incorporate the spices, then mix it with the chicken.
Add a squeeze of lemon and salt to taste.
If you want to add grapes, mix them in at the end so they don't get squashed. If you want to use apples, soaking them in a bit of lemon juice while preparing the salad can help to keep them white.