So your robot is going to trail a USB cable connected to your laptop? Fair enough. So open up the serial monitor, type a character and in the Arduino just do a Serial.read() to get the character.
Then do whatever you need to do to get to wherever your character is telling you to go. When you get there stop doing it.
You might want to look up the switch...case command as a way of doing different things when different characters turn up.
Steve