Hi,
Your radiator is sitting just behind the rear tires. Be sure to wash it once in a while. Even municipal busses require washing the radiator every 90 days (well they run 2 shifts of 8 hours, 7 days a week) and they never see a interstate highway or many hills.
Yes our mountains are much higher than what you see back east. I know a friend was in a town in Virginia, and he asked about the 'Mountains'. A lady proudly stated that their highest mountain was something like 4200' elevation. He said that the pass from Los Angeles to Victorville is 6500' and that is the pass between the mountains!
The highest mountain that you can take your motorhome on is Pikes Peak, at 14,070 feet. Yet I would recommend taking a car or rental car up that mountain. It is the highest paved roadway in the United States. They have a race to the top each summer. It is just west of Colorado Springs.
Have a great time out west. I hope that you have a chance to visit Sequoia National Park, and Yosemite NP. They are both wonderful!
Fred.