Responding to your Grand Cherokee. I use a Yakima Rack on top of a Dodge Journey and put the Frontier 12, 80 plus pounds up lone no problem. The rack has a telescopic slide rod. google it. Works great.
Nucanoe for stability! I fish from a frontier 12 and love it. They have a new model out now or out soon called "Flint" $999.00. The Frontier has a 650 lb. payload.