This leaves the U.S. with a route to the north that must cross 14 different countries, including Russia, Uzbekistan, Tajikistan and Kazakhstan, before it ultimately ends at Estonia and its Baltic Sea shorefront. This requires a herculean effort of diplomatic and customs negotiations, Baca says.
"You end up with this political-military dynamic that you have to cope with, and then you have to cope with issues that are routinely commercial interests, like customs authorities and cargo that is allowed to go through certain countries," he says.
Food cannot be transmitted by air, and the military also cannot openly transport pork products by ground through many Muslim countries, such as neighboring Pakistan or other countries to the north. Logistics crews often get creative by labeling these sealed shipments as simply "meat" instead.
Weapons, on the other hand, may not be transported by land. Pieces of equipment clearly only intended for military use may have to be covered as it travels through this string of countries.
Even if the U.S. decides to employ the so-called "zero option" and withdraw all troops from Afghanistan, not all of this equipment will accompany them. There is simply too much of it and it would cost too much, Baca says.
Top Marine Gen. James Amos said in June that the corps is "not leaving a single thing" behind in Afghanistan, except for what it donates to a foreign country. That loophole may account for a lot.
As much as $7 billion worth of military hardware, office equipment, computers, electronics or other devices that have outlived their serviceable life or deemed not economically worth moving will be donated to the Afghans or destroyed, Baca says. Some of the rows and rows of Mine-Resistant Ambush Protected (MRAP) vehicles and Humvees that line the depot yards at Bagram may also be destroyed instead of shipped home.
Donating this equipment remains a concern in a country where the tools of previous wars are often used to fight the next one.
"That's a risk," Baca says, "but at some point you have to have some faith and trust our partners that if the equipment is donated to them, they have the ability maintain, sustain and keep it for their use."
The clock is ticking on moving all of this equipment – and deciding how much should be left behind for the enduring force.
Baca plans for 10,000 troops to stay behind as an estimate and placeholder until the U.S. announces the precise post-2014 plan. Conversations with other logistics experts in Afghanistan yield similar estimates before the White House releases a tangible target.
Pentagon spokesman George Little told reporters in July that the end of 2014 is a long way away. But for those on the ground, it's a different story.
"If we were told right now that we were going to zero, there is enough capacity that we could complete the task," Baca says, adding that becomes exponentially harder the closer these units approach the end of 2014.