Go inside the Zero RC toy shop. Behind the cashier is a game being sold. That game is Grand Theft Auto: Vice City. Additionally, go to the counter inside the Zero RC toy shop. You will see a rack of action figures that includes Tommy Vercetti from Grand Theft Auto: Vice City.

Buy the house in the Carlton Heights area (near the Go Kart Track). Go inside and look to your left. There should be a hallway. To your left should be your wardrobe. Look to your right and walk through the first door. After it opens, look at the picture above the bed to see the Diaz/Vercetti mansion from Grand Theft Auto: Vice City.