Greg,
I don't want to be critical of what you have done, it looks like a quality job, but I would be concerned about your air scoop on the radiator. You have reduced the surface space that the fan pulls from significantly, therefore reducing your airflow through the radiator. Pulling mountains may not produce enough road speed to force air through your scoop. Just my opinion.
Also, you may have exceeded the legal limit on the width of the bus.
Have you driven the bus with the new scoop on? If so, what difference, if any, have you noticed in the engine temperature?