I think you will find that your mileage will not be very good, but it's gas engine that was built for towing, not cruising. I had a Vortec 454 and when switching to a diesel got about 40% better in-town mileage and almost 50% better mileage when towing our FW and boat together. When buying the first diesel diesel fuel as less than regular unleaded gas, not diesel around here is about $.70 higher. Go figure, less refining, no significant additives and the price is much higher. Kinda like when they took the lead out of gas, the price went up because ?
2012 GMC 2500HD D/A Crewcab
2012 Jayco Eagle SuperLite HT 26.5 RLS
2009 Crestliner Superhawk 1900
2013 Polaris Sportsman 550 EXP
2008 Polaris Sportsman 700 X2