[x42bn6]

When a unit enters region 1, use an If-Then-Else action that generates a random number in If and compares it with 0.5. If this number is less than 0.5, then go to region 2, otherwise go to region 3. I'm not sure of this wander thing, though...

Problem: Warcraft III does not have a fully random engine. It generates a seed and this seed is consistent for the map irregardless of time. So you will have to play around a little with random events, such as generating a random number every time a unit is selected, to keep the generator moving. Unless there is a trigger to start the randomising.*