Gail, thanks for your response, and that is a very interesting letter, indeed. Even Sardinian born William Biggis (surname also shown as Biggio, etc.) is noted as being a buddy of Bethard, as well as several other members of the crew mentioned. I do have some of the data relating to Bethard at my site, including his death data, but will include some of the other data you provide, including his possible birth in Kentucky. [This can be further checked out at the census records, at Ancestry.com, and I will do so shortly.]
With your permission, I will include the additional data, including his marriage details. Do you have his wife, Mary's, maiden name?
Will attempt to locate other data from a number of other sources.
Will also need your town and state of residence to include in the source notes, and, if it is okay with you, I will also include your e-mail address.