I've always found that I ride much better technically if I don't know the road. The worst thing ever is to practise a route, for me. This because you learn how things are when you do the practise and don't read the signs properly on the day (I mean all the signs - not just the metal ones). Plus there's that little bit of caution when you haven't a clue where the road is going, which the examiner is sure to like.
A point for the different sections of the route - they are there for a reason. If you find yourself on a single track lane, its ALL about safety. All your emphasis must be on speed/road surfaces/hazards etc. There's no prizes here for going through fastest.On the other hand with a dual carriageway, your consideration has to be riding with confidence/keeping with traffic flow/making progress etc. The examiner is not going to be impressed with someone holding up an abnormal load. Yes, safety is always first but when there's nothing else to think about, quit wobbling and get up to that speed limit.