This is a bit second hand info but when i was in Bam i met a Korean couple of guys who couldnt speak that much English but from what i could gather they had just come from Pakistan and Afganistan. It seems the road to Kabul from Peshwar in Pakistan is open and reasonably ok?? They only went to Kabul as far as i could gather and indicated it was reasonably ok?? Alot of UN/American soldiers and journalists about.
They also indicated it was quite expensive cos of the soldiers and journalists.
A second english guy at the guest house had a visa for Afganistan, that he got in Esfahan i think?? He was considering it.
Maybe this helps your decision.
Some day so soon....