I have a 2012 and the backup camera is definitley nice to have. I don't think I would buy another truck without it after having it. As mentioned dual batteries are standard and I would think dual alternators is overkill. Those are really only needed for service trucks IMO.
+1 on adding an in the bed 7-pin connector. You don't need the 5er wiring provision though. Hopkins makes a nice in-bed plug that connects into the existing wire harness near the back bumper. Very clean install and I much prefer it over using the bumper plug and having the wire hang over the tailgate.
After you get the truck I highly recommend upgrading the shocks. GM shocks are******and only last about 20K mi. Can't go wrong with Bilstein 5100's. My truck rides so much better after installing. Wish I had done it right after I bought the truck. Also recommend adding a steering stabilizer. Mount is already on the truck but GM scrapped the shock due to cost cutting... Bilstein also makes a nice stabilizer for these trucks.
