The book of letters to his sister is interesting, but not a help......seems all Gordon wrote about to his sister was of his religion and self doubts -vs- his faith; nothing of any particular specific import as to travels or outside activities.
Looks like my only hope is to discover a source for his diaries from the early 1870's.....

That said, the rifle does shoot nicely, no pictures due snow, ice, & cold......
- Mike