Since it has warmed up here in MD I couldn't resist taking my 5th wheel for a test run. I live in Emmitsburg, MD and drove up about 40 miles past Sideling Hill Rest Area on HWY 68 in western MD. The truck performed better that I thought it would going up the hills and down. Going up sideling hill I had it on cruise at 65 and it held that speed. Going back down I did not have to use the service brakes at ALL. I had a 2005 Ford 6.0 and going up that hill the best I would have done would have been about 40 and going down I would have had to use my service brakes numerous times. I was pulling a 12000 5th wheel. I average 10.6 mpg for the 160 mile trip, that was hand calculated. The EVIC stated 10.8 mpg. I was very very impressed with the truck!