I never really calculated my 96 because the odometer doesn't work. Only way is to look at a map and do it that way i guess.
On a side note, I did make it from my work (philly area) to Orlando, Florida, and back into Georgia before I stopped to get fuel. But that was with the bigge truck that has twin 75 gallon tanks. Best milage I got from that was 9.5 MPG when I went to Portland, Maine and back. That used up a little less then half a tank.