The longest run of the mountain would have to be the Flapjack to the Riva at 4.5 miles. You are tired after that little jaunt (of course I was out of shape at the time.)
The most challenging hill is the Prima Cornice. Personally I have never skied this area, but I am told it is quite a thrill.
The best view of the mountain would have to be the patrol headquarters where Chairs 4,5, and 11 meet. You can see from that are the amazing view of the 14,000 Mount of the Holy Cross.
Vail is worried about the competition of surrounding areas and treats their guests well. They have the largest network of highspeed lifts in America making your time spent on skiing instead of waiting. This is one of the reasons I love Vail!