There are lots of activities that you can do on the water in the Newport Harbor. There's a variety of rental companies that are easy to rent paddle boards, kayaks, or an electric duffy boat to ride around the harbor (bring your own food and alcoholic beverages).
Each city along the coast has a beach with a different vibe. Many have restaurants and stores nearby. If it's warm enough, pack some snacks, beverages, and towels to lay out in the sun. One of our favorite things to do is brunch in Laguna Beach then grab ice cream and coffee to enjoy while watching people play beach volleyball at the corner of PCH and Broadway.
Disneyland is about 20 miles away. If you have an extra day to spend in Orange County, it's a fun activity for everyone, no matter how old you are!
Lido Marina Village in Newport Beach is a waterfront area with great restaurants and boutique clothing and home goods stores.