Writing Creative Nonfiction

Well, big news is that I've actually started writing, which is none-too-soon as the manuscript is due at the end of June.
This whole book project came about because of a course I took with the simply wonderful Jan Cornall on Creative Nonfiction. I wrote a long piece on my history with Buddhist monks, and a publishing friend read it and the rest is history.....
The genre of Creative Nonfiction has always been a favourite of mine - indeed, among my favourite books are In Cold Blood and Midnight in the Garden of Good and Evil, both accepted classics of the genre. People don't normally associate travel writing with Creative Nonfiction, but of course it belongs firmly within the confines of the genre.
I have been enjoying and finding very helpful Theodore A. Rees Cheney's Writing Creative Nonfiction - surely the bible for those in the field? He has lots of interesting and helpful things to say, and at the moment I am struggling with his chapter on character. There are one or two key characters in my book (apart from myself) who are, naturally, real people to whom I am quite close. I have been finding it difficult to write about them - am I saying too much about them, or am I assuming the reader knows too much? And how do I avoid making myself sound very clever and those characters appear very simple and often silly. This is a real concern for me, because personally I hate reading authors who I perceive as arrogant or unaware of their own sublime stupidity. I always like grumpy old curmudgeons like Theroux who aren't scared of making themselves appear thoroughly stupid, or someone like Bryson who casts himself as the bumbling fool, and thereby avoids charges of arrogance.
I am also aware that I am a Western man writing about Vietnamese people, and with a head full of Edward Said I am terrified of coming across as a post-colonial dilettante and cultural plunderer oozing with condescension. I don't want to make the Vietnamese people, especially my dear friends, appear quaint.
But maybe that's a lost cause?