The servo was an easy fix. Joystick stuff starts tomorrow.

I do have one concern, though; the Arduino works fine controlling all servos when plugged in to the computer via USB, but plugging it in to the wall with a 12v adapter causes it to falter greatly. I'm hoping it's because of the amperage being too low and that it'll run alright with a 9v battery. Otherwise, I'm going to have to do more sniffing around, I guess.

If worst comes to worst, I'll remove the back two servos and put a regular wheel in the back.