Final answer:
To view the Long Valley caldera, standing at the peak of a mountain offers the best vantage point due to the elevated position and panoramic perspective it provides.
Step-by-step explanation:
To get a good view of the giant caldera that is Long Valley, you would likely want to stand at the peak of a mountain. This vantage point provides an elevated position where the panoramic view of the caldera can be fully appreciated. Looking over your left shoulder from a mountain peak would give you a comprehensive view of the scale and shape of the depression, enabling you to take in the vastness of the geological feature. By contrast, driving through the valley or crossing a river would offer a more limited perspective due to being on a lower elevation, while descending into a canyon would direct your gaze downwards rather than across the broad expanse of the caldera.