Park in the public parking lot across the street from the Montage Hotel, walk around the Montage down to our favorite beach, Treasure Island! The hotel is also gorgeous to have a drink :)
http://www.visitlagunabeach.com/listings/Treasure-Island/1223/
If you are flying in early and have enough time for a day trip or overnight stay, check out Catalina Island. Rent a golf cart and ride around this gorgeous spot off of the Southern California Coast!
Take the Catalina Express boat from Dana Point and you will be on your way!
Crystal Cove State Park has 3.2 miles of beach and 2,400 acres of backcountry wilderness, which is awesome for those who love to hike and/or go to the beach!