What is the dramatic function of Walsh's letters home to his wife in Pollock's Walsh?

In
Pollock's play, Walsh, the letters included take place between James Walsh
and his wife Mary, as he is stationed in the Northwest Territory of Canada (at Fort Walsh) and
Ottawa, where Walsh's family lives.

The content of this correspondence serves
several functions. First, it is through these letters that the audience learns that Walsh's job
has isolated him from the world at largeand even from his family.

You'll think I've got a touch of prairie fever, but the solitude here, the emptiness of
these Great Plains, fills me with a sense of timelessness.

Second, it shows too that the world outside of the Northwest Territory is unaware of
the demands, the politics and the heartbreak that a leader such as James Walsh faces. First is
Mary's statement of the propaganda and/or rumors reaching Ottawa (a center of civilized life,
far removed from Fort Walsh):

Here in the East, we're
always hearing grand tales of Major Walsh...how he's subdued the Sioux and Sitting
Bull.

This is, of...