I?m agonizing over the need to buy a new truck and could use some advice from someone with equipment similar to mine. This Fall I traded my popup for a 2006 Jayco Feather EXP 23B with a Gross Vehicle Weight of 4950 lbs and a cargo capacity of 915 lbs for a total GVRW of about 6000lbs. My tow vehicle is a 2002 Ford F-150 Supercab, 4X4, 5.4 liter V8, 3.55 axle ratio, rated for towing a loaded trailer weight of 7,500 lbs. Towing the popup I averaged about 15 mpg on the highway. After purchase I towed the new trailer to a nearby campground for a shakedown cruise, but have not had it on a long distance trip yet. I live in Ohio and typically make 2 trips to Florida each year and another 6 to 8 trips each year to Lake Cumberland in Kentucky (4 hrs each way). I read in the Forum that the F-150 is not a great (stable) tow vehicle and am considering stepping up to a F-250 Diesel but I keep having 2nd thoughts. Especially about the economics. Any idea what I can expect in the way of gas mileage with my current truck and new trailer?8-9 mpg? Will the mileage of the Diesel be in the 13-14 mpg range? Is the 1500 lb cushion (difference between tow capacity and GVRW) enough to provide a safe ride? Thanks for any and all comments.