I was luckier with Alexandra D.N... found more books. You could start with:"The secret lives of Alexandra David Neel" by Barbara and Michael Foster, then "My journey to Lhasa" by Alexandra herself.
Go on with "deeper" readings:
-"Magic and mystery in Tibet"
-"The secret oral teaching in Tibetan Budhists sects"
-"Initiations and initiates in tibet"
-"Immortality and reincarnation: wisdom from the forbidden journey"
If you travel in France you must go to the foundation in Dignes (south of France).It's really worth the visit. Marie-Madeleine Peyronnet the former secretary(whose nickname was The tortoise) is still there and the house is very lively full of students...In Paris the Guillemet Museum still has original writings...We visited the foundation with your son who was 6 or 7, and the guide explained him so many things he could easily understand. That was great. Alexandra's bedroom with a tiny bed, a picnic table and a lampshade made out of a sheet of newspaper.
I'm not a budhist, so of course I only give the feelings of an atheist(???though???) maybe religious people would discuss about Alexandra...
But even so, born in 1868, she visited Tibet on foot, and at more than a hundred years old she wanted to renew her passport...Her journal is sometimes ever so funny: "I want to talk philosophy with my husband but the only thing he has in mind is stroking my legs!"The famous husband was though very patient she said she would be gone for a few weeks and came back years later...Theodore Monod and Alexandra should have met!!!Alexandra was sometimes a pest very selfish, but she really was great...