After having a nice brunch in Bay Ridge, make your way down to the water. You can't walk over the bridge, but the view is wonderful from the long walkway by the water. It can be difficult to get there without a car, but buses do come close. Otherwise, take the R train to Bay Ridge and just keep walking west. There are several crosswalks over the Belt Parkway.
Driving, just take the Belt down past 62nd Street and park in any of the lots on the right hand side. You'll see kite flyers and sun lovers and just plain lovers enjoying the strip of walkway and grass that frame the water.