That's amazing to still have correspondence from the 1800's. My grandmother had much and collected all her mail.... the only thing we are left with are a few very important post cards from the early 1900's. My grandmother was born in 1900, so she had a large collection of cards, but only a few with the Borger connection. I do know that there are a number of Vancouver Islanders who have Tlingit blood lines.... the Hunt family of Fort Rupert is one of them. the Hunt family broke into several surnames over the past century and a half.....so you may come across that surname in your lineage? If you do, they are still going strong here on Vancouver Island and in BC....many being artists of world class.
Yes, in my diggings in Ancestry, I came across much on Joseph Borger of Port Blakely. I see he ended up with a native wife who had a previous child from what looks like another relationship. I am thinking, this was the Joe Borger of the Klondike, but I can't put all my eggs into that one basket.... but, he was the only one and he had the ties to Alaska through his mother's birth....so yes it is very strong that he was my relation. But, it is the journey of finding out for sure...lol.
I hope we do find a connection.... it is such a small world, who knows. I do have many connections to Washington State over the years....many on my mother's line and many on my father's line.
Many cheers from the island, Rocky