A glitch in Grand Theft Auto Online allows players to return to North Yankton, the area where Grand Theft Auto V‘s prologue takes place.
First you’re going to need two players to make this glitch work. The first player must start an invite only session of Grand Theft Auto Online. Then all you have to do is replay the single-player prologue until you get to the part where the garage door opens and the police start shooting at you. At this point run to the left once you have passed the police vans, then pause your game.The player in GTA Online must then invite you to the session.
One you are in the GTA Online session grab yourself a helicopter and head to the bottom right of the map. Once there, you should see some mountains floating in the distance, keep heading towards them and eventually you will see North Yankton, which you are now free to explore.
You can watch a full video walkthrough of the glitch at CVG.