Where are the swing sets in gta4?

Answer 1

The swingset is located on the Broker and Dukes island near the bottom right. Close to the Faustin's missions but more north

Answer 2

there is one on the first island south, it should be close to the 8-ball place, so keep travling up until you see a break through on the highway wall, you should find it there.

Answer 3

There are several swing sets around the city and they are playground in Firefly projects, back garden of a mansion in Westdyke, junction of Owl Creek Ave and Tenmile St.