Belt - Add a nice red belt from DVF.
Sandals - Wedges are a must for the sandy lakefront beaches, and these Nine West sandals are cheap enough on sale that you won't mind if they get muddy.
Clutch - A simple clutch in turquoise and gold for $80.
Earrings - Garnet and gold drops.
Bracelets - A set of basic gold bangles.
Pashmina - Bring an inexpensive ivory pashmina from Cost Plus as a layer if it gets cold.
Sunglasses - A pair of aviators from Target.