Is that not the road used by Ewan McGregor and Charlie Boorman in Long Way Round? Because if yes then that road was passable, but even in the summer they had to cross several streams and it looked like the only people driving it were locals in old 6x6 Kamaz Trucks.
In my personal opinion it's the weakest of the three - way too much time is spent on technical problems with the bikes and cars and very very little on culture and people of the countries they go through, it picks up in the last 3 episodes but that's 3 out of....11? I also hate the Americanised editing style where even in perfectly mundane situations there's extremely dramatic music playing, rapid cuts between scenes, and worst of all, episodes ending on cliffhangers like some cheap TV drama. Long way round and long way down had far more soul to them. But hey, that's just my opinion.
And the other thing - I really wish they waited just a year or two with this adventure, the tech they used was literally on the verge of maturing but 90% of their problems were due to driving prototype vehicles. Literally just a year after filming, there are both electric cars and motorcycles that don't run effectively alpha firmware.
