I am planning a trip to Yellowstone in June and am looking for suggestions relative to highway selection to West Yellowstone, MT. Traveling in a 30 ft Class "C" with a tow car. I will be coming in from Kansas City via Interstate 80. From I-80 I will head north on either US 287 at Rawlins, WY or US 191 at Rock Springs, WY. Which of these two highways would be the best choice and why? Thanks in advance for your help.