Towing in the Rockies - Towing Capacity Safety Margin?

My dad is a member of this forum (Diesel page). Dad used to be an OTR driver for many years as both an owner operator as well as driving a company truck whoever he may have worked for. He was also in the U.S. Navy as a diesel mechanic before he retired after 20 years. He could tell you pretty much anything you want to know about diesels, past and present. Anyhow, he thought this forum to be pretty knowledgeable. I hope this helps FWIW.