28 feet and a 6000 GVWR? Not practical nor reasonable. 6000 GVWR trailers generally are around 18-23 feet long even in a light weight trailer. Heck some tent trailers can weight that much. I suspect your either mis reading the brochures or are being misled by an unscrupulous salesman.
Most brochures now days do not list GVWR, only a dry weight which is unreasonable to consider. Again, your 1500 ecodiesel is a nice every day driver! And adequate for a small light weight trailer like a RPod. But a 28 foot slab sided trailer? NO WAY!