I figured I’d try the GTA3 ambulance missions, since the rewards are useful (health and adrenaline pickups at the hideout, and infinite running stamina). However, after numerous attempts, screw that. The ambulance tips over way too easily, the entrance to the hospital to drop people off is really narrow, and gang members would pull me out of the ambulance, instantly ending the mission.
So, I wound up starting on the missions for the Yakuza on the new island instead, and opened up a bunch of other mission-givers. I’m sure something’s going to drive me away to the next part of the city, though…