I owned a 2005 Isuzu cabover 4500 with a 18 ft. box, and iwas diesal. No liftgate, automatic, ac,power windows. I made local deliveries of 200 to300 miles a day with 8 to10 stops. I am a big guy, 6'4"" 400 lbs and had a hell of a time getting in and out of cab but drove nice, tight turning radius but had problem hitting head on ceiling on rough roads. I did average 14mpg on highway, and 9 to 10 in the city. I end ede up tradeing in for a 2005 gmc 4500 18 ft box,diesal,auto,power everything mostly for comfort and got around 10 to 12mpg average. Both had low resale value when sol with low miles.