My father in law is in his eighties and served as a Swedish diplomat in Moscow in the 1960's (among other places). I know he too would love get a chance to read some of those letters.

Did he have any thoughts on the Gulf of Tonkin incident?

There are sites that let you set up an email capture box in a few minutes (such as mailchimp). Doesn't have to be a full landing page.

There's definitely interest!