The Alpine Visitor Center is on top of Trail Ridge Road and is an obvious stop when you reach the top. Air is thin and even native Coloradans can feel the altitude. If you are from lower elevations, be careful about physical exertion. There is a medical station on the park ranger side of the center and they can help if you feel any distress.
On a clear day, you can practically see to Kansas and the views are 360 degrees.