Seriously, the vehicle break in period is almost a non event for an Av. The main consideration in GM's suggested plan is not to exceed 55 mph for the first 500 miles, vary your speed (don't set it on cruise and forget it) and TRY not to emergency brake until that period is over. Basic common sense. The only thing I would add is to do a fluid check more often than normal, and cycle every operating system to check all the functions ( A/C, heat, trailer mode, etc.) so you don't have any surprises on the road.
Check your tire pressure. I do not trust the dealer to do this. They may stoop low, but not to check tire pressure. The door frame tag on my Z71 states 30 psi.
With that said, I run 36 psi. I think you will find most people, on this site, run 34-36 psi in the 17 inch tires. My truck seemed to wallow with 30 psi.