First of all, the drive to this place is awesome! You have to cross many bridges and the route is very scenic. We paid $10 for the parking (Field 5) and there is ample space even during weekends.
There is a boardwalk from the main beach to the Fire Island lighthouse. The lighthouse closes by 3:30pm but the views outside are really beautiful too. The beach opposite the lighthouse is less crowded but equally good and has great waves.
There is an amazing restaurant at this beach that serves drinks, food and ice cream, with several options to choose from. Restrooms and shower areas are right beside this restaurant.
There is also a paid pedi cab service, located at the parking lot to take you to Kismet. It is not very easy to cycle near this beach as cycles aren't allowed on the boardwalk and the other paths are too gravelly.
Overall, we loved this beach! It is perfect for a relaxing afternoon on a hot summer day.