If you question the validity of FF's autobiography only because "it's too well written," you need to read more of FF's writing--she was an absolutely brilliant writer. But, that aside, it is largely ghostwritten, by FF's late-in-life friend Jean Ratcliffe (who dedicated the book to herself). It's highly sensationalized and contains numerous errors of fact. You can read more about it at:
Hi
i know she was a good writer, however some of it seemed,as you say sensationalized and all the religious stuff at the end, finding peace through god etc seemed a bit obvious, dubious. It reminds
me of errol flynns biography where he dictated and earl conrad kind of organised it all together etc. I have read many more sensationalized texts
regarding Frances Farmer,a lot of it i hope isn't true.