Fuel economy on Thor Super C

Thanks guys for the updates. I am not even considering the GVW since Texas does not require a CDL for an RV. I really want more torque and really like the Ford 6.7L Diesel, since I have my pickup truck with that engine and it is quiet and strong! (like my last girl-friend LOL) I MUST know the fuel economy before my purchase of the new vehicle to verify the price diff of Diesel v Gas. ALSO, anyone have any info on the house-hold type frig in the Super C? Fairly large inverter with only 2 batteries? Auto start on the gen is great but TWO BATTERIES??? AND, it is not even an energy efficient frig! :( Either the gen will start often to charge the batteries or??? Something just does not seem right with that configuration. Although, I fully intend to add numerous solar panels to help to frig inverter draw during the day. Several times I have used my current Class C to ruff camp, at places like Burning Man 2012 (look it up, great party) During that 8 days on a dry lake bed in N. Nevada, I ran my gen 4hrs per day, had solar panels, and did just fine, BUT, I have a standard RV frig. I also understand the home style frig units cool better. Thanks Jer-beautiful day today in Texas! :)