One thing I have not read in this thread was propane injection. While I am not thoroughly versed, what I have read is that it is great at cleaning up an overfuel truck, but that it also can be programmed, to augment the diesel used, extending range, and increasing MPG.
quick searched article here, on Dodge:
Dodge Ram Cummins Diesel Propane Injection Performance | Mopar Muscle Magazine Article at Automotive.com