I have a 2005 F150 with the same size engine. Last year's big trip from the south plains of TX to the mountains in southern CO I averaged 9.6 mpg on the way there and 10.2 on the way home. Conditions were good with no heavy winds. However, on another trip to a state park a few hours away , completely flat drive, but heavy head wind.....5.4mpg! It is shocking to actually be able to see the gas gauge move! Doesn't help that I have the 21SS that is a little taller than the other Roos.
Michael, Cristina, Anthony, Cocoa Puff, Cookie, Blossom, Tosca, & Heidi
2012 Rockwood Roo 21SS