Need help with left to right random movement

Hi all. I’m trying to achieve random motion of my movie clips limited from stage left to stage right. I’ve read the following tutorials:

http://www.kirupa.com/developer/mx/continuousmovement.htm

http://www.kirupa.com/developer/mx/random_motionMX.htm

both are helpful. However, I don’t want mouse position to affect anything (as it does in the ‘continuous movement’ tutorial). The ‘random motion’ code is pretty close…if I just knew what part of the code to modify to limit motion from left to right.

Can anyone offer some advice?