Fuel economy on Thor Super C

ACTUAL OWNER OF THOR SUPER C - Just purchased a 2014 Thor Super C with the 6.7L diesel engine last week and drove it back from Dallas Texas to Houston. I traded in a 2010 28ft Freelander with the V10. I must say this engine is strong and quiet compared to my old one. I like the power, and the extra room in the cab since it seems like I am driving my pick-up truck. (Yes, I also have a 2010 F450-KingRanch with the 6.7L) Seems the prep crew parked my vehicle and did not plug it in nor set the gen to auto start so batteries were dead. Coud not get the 12V to work so ran gen all the way home since I had no 12V ~ discovered the safety breaker (under bed) tripped, reset it and all seems well. I will drive it to Lake Charles this weekend for a short trip, seems we cannot get rooms and the RV park is full so run gen and live large. I checked the fuel economy and even reset the meter several times to get various readings. So for - 8.5-10.5 mpg. I will fuel up and NOT reset it this weekend for a more accurate measurement since NOT ONE PERSON was able to tell me the fuel numbers before I made my purchase. Also - yahoo groups has a "Thor Super C" group, please feel free to post there also. I started the group and the link is here - Jer in Texas - "Burning Man 2012" and camping off grid lots.