Just returned from Phoenix Az, with my Dutchmen Classic, 27 ft 5th wheel, w/slide. Pulled 4000 miles round trip from Kokomo, In. I have an Edge EZ, set on level 2. This Edge Chip is one of the new ones. I run 65 - 70, aveg mpg 10.5. No trouble with the hills. This 03 Dodge HD, 2500, 4x4, quad cab, 8ft bed, did a very good job of pulling what ever was out there. Drove the southern route, Dallas I-20, down to I-10 and into Phoenix.