Based on a few things in George's call to dispatch, I don't think he was near his home. For one thing, he began to give out his address as 1950. The only 1900 block/building group I see on the map of the complex is in the southwest corner of the complex. Also, Zimmerman told the dispatcher that he didn't know the address where his truck was parked - unlikely if he was parked in front of his own home.
As for Martin not simply running all the way home, it is possible that he, like Zimmerman, didn't want this stranger to know where he lived. Though an athlete, I doubt he could have covered the entire distance before Zimmerman was able to cover the distance from his truck to the north end of the walkway which could have given him a view of which house Martin ran to. I think it likely that Martin did run and then ducked between one of the building hoping George would lose sight of him, which he apparently did.
We have George's statement given after the fact that indicates that he headed back to his truck after losing sight of Martin when Martin approached him but no independent collaboration. Martin's girlfriend claims that Martin was the first to address Zimmerman, asking him "Why you following me?" but unless Martin said something about Zimmerman spotting him or him telling her that he was going to surprise Zimmerman, she would have no idea who caught sight of whom first. If George was still looking around for Martin, it is possible that he spotted him and that Martin was just the first to speak.
There's nothing to back up George's statement about Martin approaching him but there's nothing to contradict it either. And the police can't arrest someone solely because they MIGHT be lying. It will be interesting to eventually see all the evidence -- the EMT report, the autopsy, forensics on both their clothing, etc.