I don’t have a photo from the perspective you mention. However, in being very familiar with that park, I can tell you this. The courts back right up to the playground, the courts are fenced in. Even though mom was sitting in a car, some ways away, there was still a view from her car to the playground. Perhaps not completely unobstructed, but enough that she probably felt comfortable enough.
I think, if this is a stranger abduction, it is easy enough for someone to have been parked behind the storage buildings that the 3yr old mentioned/pointed out. It is a secluded area. It has some old tennis courts, that appear unkept and caged storage areas, like platforms that are used to store park equipment, containers, lights, etc. this area is not as populated as the other areas of the park.
It would be quite easy for someone parked here to have a pretty decent view of the children playing on the playground, from between the two buildings and easier still to walk between these buildings, unnoticed and approach a child, or call them over, etc. Even lure them further over to behind the buildings where a child could be put into a car and driven away without getting much attention. It’s a busy park, especially that time of day, but busy doesn’t necessarily mean everyone is paying attention, but rather chaotic busy where things may not be noticed with the noise levels of nearby practicing football teams, cheerleader practice, kids screaming on a playground and the sounds of basketball.
I’m posting a few maps of the area to put it in perspective.
Key:
Blue is where mom parked
Yellow is swingset
Green is basketball courts
Red is storage buildings
White is secluded area behind storage buildings
Black is paths out/roads
Forgive the roughness, I did these hastily.
Also, from aerial view, areas seem further away than if you were standing there. See maps with distances measured.
I may go out there later as they are having a candlelight vigil, maybe grab pics, if I get there early enough.