i'd definitely go with the richie unterberger 'day by day'.  it's certainly exhaustive and has tons of good anecdotal stuff from the band members and others, plus a great selection of photographs.

i recommend that you try listening to some brian eno, yo la tengo, talking heads, luna, etc.

lou also has said that he had doug sing 'candy says' because he (LOU)
could never get the innocence and naivete that doug brought to it- largely because doug hadn't known candy and didn't bring any preconceptions to his vocal delivery.  and while i love reed as a musician, i don't take his judgement of people all that…