I would not think of it as dangerous. Apart from the danger of car accidents etc etc. Some interesting places on the way, Turkmenistan is particularly strange, like the slightly moderated not known little brother of North Korea.

It took 11 month an 40k km all in all. But it was 80% detours. Had to leave my car at the boarder to China. No chance to take it there. The most magnificent place on the way was Iran for sure. Lovely people with a hate for their own government and not afraid at all to voice their contempt for religious fanatics, the city dwellers at least.