how much of the terrible narration would I have to sit through?

I just started watching this and got interrupted, so now I have to decide if my negative impression is strong enough to make me skip it, in spite of my fondness for Leigh. I only got as far as her arrival in Rome, where her situation is put into context by a narrator who sounds as though he mainly narrates educational films and true-crime dramas. It is so jarring and flatfooted to express William's ideas with such an unmusical voice that it makes me suspicious of the movie as a whole. So my questions are: a) is there a lot of narration, or will this stop soon?) and b) is the bad narration and overwrought score representative of the overall approach to the film, or or they just a couple of blemishes in an otherwise worthwhile endeavor?