n4hwl,
You are doing it just right. Keep the engine geared and the peddle floored so you maintain that 1800-2000 RPM range. The engine is designed for this kind of use and, if anything, you are doing the engine some good as the diesels are really designed to be worked hard. There is a governor as well to keep you from over revving so if you are in too low of a gear and you have it floored, the coach will not go any faster than the max RPM will allow without automatically upshifting. Yes, I have been over the Eisenhower and Vail passes many times. We do it at about 30MPH with the pedal floored in 2nd gear. It adds about 5 minutes to the trip compared to what my GPS says it would have taken at the speed limit. No worries, I'm not in a hurry anyway!