My wife and I take our Mirage Sports to many different places (Colorado, Utah, High Sierras, SoCal), so I built this rack to carry them on the back of a motorhome. We have about 6000 miles of transporting them in this manner, with no problems. I've since added a small electric winch and swiveling lift arm, that allows me to raise or lower either kayak with the push of a button (too many old shoulder injuries!)
Hope this is helpful to someone else working on a solution. The rack is mounted to the frame, only, with no attachment needed to the coach body. This picture was taken at Gerle Creek Reservoir, west of Lake Tahoe. Wonderful lake to kayak and camp....22ft limit on the camper and no power boats allowed.