I love Delaware and New Jersey beaches but you should take into account the summer traffic. I grew up in Delaware and have many relatives in South Jersey, most of them in Wildwood/Cape May area. Whenever you leave your beach town whether it’s Lewes, Cape May, Rehoboth or Bethany, you are going to hit massive traffic, which to me negates a lot of the positives of a vacation. Lately, we’ve been vacationing in the Outer Banks in Corolla. I’ve enjoyed kayaking, gone on a wild horse tour, yoga, and a nature walk. There’s a lot more to do in the Delaware/New Jersey area but there’s a lot more people and traffic too.
If you do vacation in Delaware or New Jersey, make sure to take the Cape-May Lewes ferry http://www.capemaylewesferry.com/ and spend a day at Cape Henlopen State Park and visit the town of Lewes. Cape Henlopen is just beautiful and has a snack bar, nice bathrooms and public showers. http://www.destateparks.com/park/cape-henlopen/ Lewes has a really nice farmers market: http://www.historiclewesfarmersmarket.org/