You really don't need to use the VX ecu as a controller, just need a heater circuit and such, then read the voltage from the sensor. There are some DIY plans out there from the land down under that I've used before, I think I even have a spare PCB kicking around.
As far as cruising at a buck 30... I used to do it once a month, late night runs to LA to avoid the traffic. Just made sure to keep a keen eye out and a good radar detector on the windshield. 4 hours sure beats the normal 8 it takes. I did get pulled over once... the cop was nice and let me off with a warning.