Ultimately, we feel that we were able to prove our concept with our design. The car will hone in on a beacon, given enough space and a clear path. However, given the opportunity, a number of changes would be made:

Due to the relatively short range of the sensors, it would be useful to add some sort of a search algorithm for the case that none of the sensor signals are above a certain threshold. Something as simple as expanding concentric circles would be sufficient to find a beacon that was not too far out of range.

We would also want to attempt to improve our motor control circuitry, perhaps further exploring the use of a phototransistor to isolate the motor power and ground, removing the need to switch the motor on and off around sensor readings. This would allow for more accurate calibration of vehicle speed, as there would be no need to compensate for a period of "off" time during every control loop. It would also be useful to implement a speed control feedback loop, with something like an optical sensor on the rear wheels, allowing the software to compensate for dropping battery charge.

Finally, we would want to implement the IR colision avoidance, allowing the car to navigate around obstacles as it honed/searched for the beacon.