OK, here is the latest information directly from GM and the easiest way to accomplish a 4 wheel tow behind a motor home or other vehicle with a 2014 / 2015 1500 4x4 truck.
1- connect to tow vehicle
2- turn ignition key to accessory
3- shift transmission to netural
4- disconnect negative battery cable ***
5- leave transmission in neutral and key in ignition in accessory position
6- lock all doors manually
7- go down the road!
***The easist way to make this step simple, is to install a $16.00 RV battery disconnect box to the negative cable. There are a number of diiferent types available and the one I used has a large red plastic key that is removed when the disconnect mode is used. I had my dealer install the box as a condition of sale and to back up the warranty process. We double checked the procedure prior to signing the final papers. Simple!
This complete procedure takes only a few minutes and there are NO speed limits associated with this type of towing!