I had a 2004 Dodge conversion van with the 5.9. It was a half ton conversion van but had upgraded suspension, rear axle, brakes etc. According to the company that did the conversion (elk automotive) it was could tow 7K. I towed my jeep on a trailer with it, just a regular hitch. Other than some loss in acceleration you could hardly tell it was back there.
I live in MO so I have never driven it up or down any mountains so I can't comment on that but the power and stability seemed fine.
Schitzangiggles: We used to teach our children to fight evil, now we teach them that fighting is evil.
2001 TJ, 33 trxus MTs , W, locked, belly up, some armor.
"If you aim at nothing, you will hit it every time." Zig Ziglar