Moving Characters

Hello, I am trying to make several computer characters move around the screen. I am successful in making them walk back and forth between two locations, but it triggers all characters at once. I am asking if anyone knows what I can do to the script provided below to make them turn around and walk back at different 'times' (I guess that is the word to use). here is the script I have so far:

function turnAround(num) {
villager_speed = -.3; //ameks the characters walk to the right
setInterval(walkAround, 4000);
this['villager_'+num].gotoAndStop(2);
}

function walkAround(num) {
villager_speed = .3; //make them walk to the left
setInterval(turnAround, 4000, num); //after 4 seconds turn around and walk the other direction
this['villager_'+num].onEnterFrame = function() {
this._x -= villager_speed;
}
}

for(var v = 1; v <= 2; v++) { //just two charactesr at the moment
walkAround(v);
}

stop();

Any help on making them turn around at any random time would be appreciated. Also, the characters have two frames, one looking left and the other looking right. I have this:

this['villager_'+num].gotoAndStop(2);

to make them face right when they walk to the right, but it doesn't work...? Please help me with this. Thanks