If you are still seeking info on the Larson/Guri Espeseth connection, www.larsongenealogy.com
has quite a bit on the Larson side and does track the Espeseth family back a few generations. Also there is a Book titled "Wingwalker", written by Bernice Lee Krippene, a relative of the Larson Brothers, in collaboration with Leonard Larson, the youngest of the Larson Brothers. I believe it is out of print now, But I was able to find a copy last year thru Amazon Books. Bernice was also related to Clyde Lee (Lea) who was also (I believe) a nephew to the brothers, who attempted the first NY to Oslo Norway flight. His plane disappeared before completion of the flight.
Footnote: I am a half descendant of the brothers thru their grandfather Knud Larson, and also webmaster for www.larsongenealogy.com
I hope I was of some help to you.