How do you spend your time? Where do you like to go around the city? Choose a location that fits you and your family. If you love going to the beach together, go to the beach.
Age is important to consider. If you choose downtown, cars and lots of people may distract them. The park or the beach would be a good alternative.
A location near your home may be a good choice. So you are not stressed out trying to get to a location that could be on the other side of town.