You will surely see plenty of deserted sand on your ride down to the south point.
If your wife wants to see the light house that is the direction you'll head. There is parking as well as a museum. You can even climb it for a small fee. They have an outdoor shower and little store.
I have always used Davis Shore Ferry service. Very nice and helpful. They always have all the bait and ice you will need.
You can also rent a cabin, since your wife is joining you, if you decide to go over for a couple days. Even if I go over in July it is never to hot in the cabins with a nice sea breeze.
Please take plenty of bug spray. Especially if you'll be exploring around the light house, etc. They can get nasty back there.
Have fun, it is one of our true gems along the coast.