You should break in the rear end gear set and try not to tow heavy during the first 500 miles. I ran my <4K boat up to the scales 30 miles and back as part of my break in and scaled the truck without all the toys in it and the boat.
I tend not to use cruise, vary speeds, and don't run it for too long for the first 300 miles, taking frequent breaks to cycle the temp in the rear diff. Running around town with a few jaunts on the highway is, IMHO, a good break in.
During the no towing, I pretty much drive it like I stole it. I'll probably have much more than 500 on it before I get to tow heavy (if 16K is heavy).
Our first trip is scheduled for late June though we usually do a shakedown run without the boat end of May. Not sure if we'll be able to do that one. That will get me to where I'm confident I can pull raton pass at whatever speed other traffic will allow me to run.
Last time I did the diff service on my 04.5 at 60K the gears still looked almost like new but with a very nice even and light wear pattern.