The time cheat worked nicely. Even though cities won't load, all the cars on the road still spawn. And drive into rivers because there aren't any bridges.
And as I was flying over a large portion of water, I could see a line of lights to show that there should be a really long bridge there. When I flew down cars started to spawn mid-air and plummet into the ocean xD
Really looking forward to this game. I hope there are cheats like the old GTA games used to have to give even more replayability once I'm finished beating it.