We used to tow a 2002 Silverado. We just put the transfer case into neutral, left the key in ACC, and pulled a fuse. Check your owners manual to be sure you can do it with the year and model you have and for specific instructions.
Also check the weight capacity of your receiver and the GCWR of your motorhome to be sure they can handle the weight. Our Silverado half-ton extended cab weighed in at well over 5,000 lb. when it was full of fuel and other "stuff."