Umm yeah, roads.
When I was there last year I could do about half the daily distance I'd do in Europe: the combination of bad roads, altitude, heat, gradient and scarcity of supply points meant it was tough going. The SRMR organiser seems to have quite strenuously avoided anything even vaguely resembling tarmac in the region, and has taken plenty of passes that I wrote off as masochistic and/or too slow of I wanted to catch my flight home. In short, it's going to be a very tough race.