I haven't....and hardly any of these trucks actually have the claimed payload rating. What does your door sticker say for available payload? More stats here for weight distribution and CG
http://www.gmfleetorderguide.com/NASApp/domestic/printbook?pdftype=camper&lang=1&year=2014
Limitations:
The following 2014 model year General Motors truck models are not recommended for slide-in camper applications:
• Any pickup model with a Cargo Weight Rating (CWR) of less than 226.8 kg (500 lbs). A statement to this effect is
imprinted on the Truck-Camper Loading information label that states whether that vehicle is recommended for use
with a slide-in camper.
• C/K Silverado/Sierra 1500 crew cab,
• C/K Silverado/Sierra 1500 with 20” wheels,
Notes:
• C/K Silverado/Sierra 1500 Pickups should not be used for larger, cab-over type slide-in campers.
• Some vehicles may be equipped with exterior trim options that may interfere with installation of a slide in camper.
Using a slide in camper for these vehicles is not recommended.