So far I've used my 300 to tow a car trailer & a Uhaul trailer from oregon to colorado. The blue mountains of eastern oregon & blizzards in wyoming SUCK. I had to slow down a bit for the hills, but for the most part I kept up with traffic on I80 & 84 just fine. Unfortunately I can't drive the truck right now as I blew the head gasket, warped the head, burned 6 valves, messed up all of the valve guides, broke several rings, burned & cracked a piston. Wasn't really my intention to do all of that, but I guess I don't mess around with screwing up a motor. With all of this though, it still got me the 100 miles back home. Not interested in repeating that experiance!
Edwin