I did a lot of research the last six months on the under 10,000 gvw with SRW and 12 ft. box . In the 2005 to 2007 Fords were the most available and you would have to CUT your own hole from cab to box. AND most had the LIFT feature on the back WHICH would of been the FIRST thing to come off ( to much WEIGHT wasted ) I had my sleeper plans all drawn out to have sleeper FOLD up against wall behind drivers seat so i could have use of the whole box. From talking to dealers and mechcanics about 14 mpg would be best IF YOU kept foot out of it. But after talking to companies and other drivers I went with the chevy express 1 ton ext. with 6.0 motor . I have been using this van doing my chores and running errands and i 've been averaging about 16.5 mpg on these shorter drives SO i figure it will 17 t on highway and i 'll be happy with that untill i save enough to buy a sprinter type van .