The "backyards" in this complex are really common areas. With green grass - no fences - and a sidewalk.
I understand everyone uses these sidwalks to get around. Therefore GZ had to leave his SUV.
One thing that I saw that doesn’t get much notice is why did Zimmerman have to leave his truck to find Martin? This is a development and he could have just followed in his truck. Then I saw somewhere Martin was going through backyards and not on the street. As a community watch would that not arouse your suspicions? What was Martin looking for in back yards during the several hours he was unsupervised?
New Rules for Criminals
1) Don’t wear hoodies
2) Case your marks from the street
3) Don’t attack armed white/Spanish people
There’s a paved walk between the backyards - Zimmerman called it a cut-through. If Martin had visited a few times previously he would have known it.
If he really was an innocent boy unnerved by a man following him in a truck, it would make a LOT of sense to leave the road and take to the shortcut.
The aerial map of the neighborhood is available, you can google it.