score:5
If you don't have your own transport, your mobility will be very limited.
It still makes sense to avoid Kandahar, for safety reasons, though you do speak Persian (it appears), which will make you blend in more.
So, your most sensible route would be Herat -> Mazar -> Baghlan -> Tajikistan. You could head down from Baghlan to Kabul and back to visit Kabul.
It's a bit of a detour and requires your own vehicle, really, but Bamyan is very much worth it.