Hmm... why not give them(the people) random 'way-points' to head towards (allowing for some sidewalk sized deviation, of course) instead of a pure random direction. You could pick every street corner and/or major building enterance as the 'cardinal way-points' and they have to choose one other than the one they just had last. This type of way-point system might make them move about the maps nicer...

As for the free audio sites, I'd scroung some up for ya, but it's late. Perhaps if cairnswm doesn't beat me to it tomorrow, like he usually does , I'll try to find a link or so for ya.