Tri5 I love your GMC dumper. That bumper on the front is great.
Chris the unanswered question is still what does that thing weigh? From the angle I don't want to guess the length, but if that's an all steel bed, and its very long, you've got a real heavy truck there.
You still might be challenging the 10,000 pound towing capacity of your truck by time you combine the weight of the truck with the rented trailer. Make sure your hitch is rated for that load too.
Its been more than 20 years now, but someone I used to know was killed when a stranger's improperly loaded trailer caused an accident. Please take the extra effort to be safe.