First, a little over a quarter of it is on the GAP, which is only slightly more interesting than being a trainer in your basement.
Second, a large chunk of it (about 30% of it, I'd say) looks like this:
https://goo.gl/maps/KdzvdBhG9wV7LEAc6
And about 20% of it looks like this (high speed road with small or non-existant shoulders):
https://goo.gl/maps/2yjtwMwzfBzsmjvZA
So, in short, about 75% of it sucks.