About time that this thread got a "bump" - less than 3 weeks to go!
I ran it last year in road shoes and was absolutely fine.
The navigation was a worry beforehand but I studied the maps the night before, so they were fresh in my mind, and made my own notes about points where I thought I might go wrong. I didn't have to refer to the directions very often as I could usually see at least one runner ahead of me who had usually figured out the right way before I caught up to them! One of the lovely things about a race like this is that runners help each other to get the directions right - it's in everyone's interests not to go wrong!
And whilst the climbs in the first part of this race are significant, they are worth it for the views, and the relatively easy second half.