For us, we discovered quite by accident by adding an efficient vehicle to the house hold thereby parking until needed the diesel, would put diesel fuel in the tank from the significant savings gained by using a 100% Electric vehicle for the main work commuter over 96mile round trip per day work commuter. Savings from fuel either gas or diesel..a lot less maintance..no oil/filterchanges, no transmission flushes, no fuel filter less brake wear,etc..etc So far only tire rotations, windshield washer fluid and inspections for brake wear (regenerator braking saves the brakes) and inspect cabin air filter.
I know its not a mod to tow vehicle or trailer but having the deal we got on the EV vehicle even after cost involved..payment, insurance, electricity cost actually saves us enough to put in fuel budget if you will. Works for our family maybe not for others.