After rigorous testing, I found out how to take what was found with the G1 skip and get back out of bounds using the car on the ramp in the parking garage. We can't go straight to the fence the zombie opens however, since the zombie has not spawned. But now that the streets have collision, it sets up the stairs to the sewer in Leon's campaign to also have collision. That's the first stop.

Then by rendering the stairs, we can walk along the (invisible) railing on the side and ascend way far up, which is perfect for getting over the fences, and the car barricades out front of the Orphanage. We can walk along the edges of the map, past the Basketball Court, and once we see the Orphanage we can get down from the height by lowering ourselves on the cars.

Once you interact with the door, just like the cutscene after G1 skip you're able to progress as normal. And since you don't have to backtrack once you're inside the area, there is no chance of softlock in the speedrun.