My .02. Use the diesel. I've towed trucks, both 1/2 ton and 3/4 ton from distances like Pa. to Fl. I've towed with a 350, and with my 6.2 diesel dually. The diesel wins hands down. Towing a '46 3/4 ton on a U haul trailer from Pa I averaged 15.5 mpg, with a 6000 lb load (truck with extra 216 and tranny, and those U haul trailers weigh in at 2400 lbs themselves). With the 350/400 combo in the 1/2 ton I averaged around 6.5 mpg, and a few grey hairs on my d***. You also had a great idea(that I always use). Rent the trailer "locally" for two or three days. Make sure you go to one of the mom and pop rental locations to do this, NOT one of the big U haul corporate places. The "one way" rentals are a crime. You could buy your own trailer for what you pay for a two day one way trip. Local you pay around $65.00 a day plus tax, and damage waiver, around $85.00 X number of days. I have checked, and am not aware of anyone else that will rent trailer only. Others require you rent their truck, to tow their trailer. Be safe, and have fun
