Like I said, everyone thinks its for the engine.I am not an engineer, but I have broken in new motors and new cylinders in the aviation world. Our goal is to keep the ICP (internal cylinder pressures) low during break in. We do that with higher rpms which helps keep ICPs low. Now I am not recommending high rpms before the times that are recommend at RAM. Personally I would follow their recommendations as closely as possible. These instructions will help with future oil consumption, and wearing in (mating) of the parts.
Again I am not an engineer, but have spent a lot of time researching and looking at the evidence of proper break-in of airplane piston engines, and I have witnessed the results first hand of proper and improper Break-in techniques. No doubt one of the engineers on here can discuss this more scientifically.
So 500 miles isn’t too long to wait before towing. And for the next 1000 miles just don’t tow straight up the Rockies in a high gear.