I need to switch the motor gearing to high torque instead of high speed. Also, notice the plastic sides that I made :] Besides the motors being underpowered currently due to the wrong gearing, he works well. My rangefinder is having some issues where it won't detect anything further than 6 inches. I don't feel like spending money on a new one right now and that's enough distance for me to stop the robot in time, so it'll do for now.
I've found that the best way to mold the plastic while it's warm is to use your hands for the basic shape. Then when it gets to ~100 degrees or so, start using scissors to get what you really want. That's how I was able to make some cleaner edges. I still want to experiment with having a mold and pressing the plastic into it, but that's for the next monster.
So after I switch the gearing (which means taking the whole robot apart, then taking the whole motor apart, redoing the gearing and putting everything back together), I'm going to order an onboard compass and integrate that. After that, GPS.
This is fun.