Thank you for your advice. I have been told that it is "not advisable" but still allowable to travel to Afghanistan. Do you mean it is "off limits to tourists" via the land border?
The official advice to Australians is 'do not travel':
This has implications for your travel insurance and for the level of help you can expect if you run into difficulties while there. Take further questions on this to the Afghanistan branch.
There are no land crossing points between Afghanistan and Pakistan that are open to foreigners. The Polish couple mentioned above may have managed to find a way around this but that will have required a lot of advance paperwork and some considerable costs, including escorts. Perhaps they are filmmakers, or something similar.
The region in the far north of Pakistan has a porous border with Afghanistan's Nuristan province and locals might cross it, but these locals include militias and extremists. It is dangerous for foreigners to go wandering around this region. Even if you can escape the scrutiny and obstruction presented by the Chitrali police, the weather will prevent you from making the mistake of attempting to cross the border there.
To travel from Pakistan to Afghanistan, fly to Kabul from Islamabad or Peshawar.