The coastal artillery is defensively strong and one battery in particular is behind a riverline which will be defended by good German infantry with tank support. Forget about expanding to the west to cut the peninsula. Keep your units concentrated to use the divisional artillery to maximum effect. Drive down the east coast of the peninsula, using carpet bombing if necessary, and drive on Cherbourg. It takes two weeks to get the momentum going.
Great care is needed to avoid too many steps of armour being lost in the bocage.
However after two weeks US Corps artillery will continue to grow to damaging proportions and ultimately shatter the defense outside Cherbourg. The German will ultimately let go of his tenacious defense as he sees more and more of his divisions being chewed up. By the end of June he should have formed his new line at the base of the peninsula in some depth. Supply is an area of the battle that deserves special treatment. For the Allies it's management will control the pace of the game.