The Russians resupplied by air
The opposition forces had great success against Russian convoys by hitting the first and last vehicle, trapping troops and supplies in the middle. When they went to air supply the opposition still had some success by stationing AA machine guns in the mountains surrounding air strips.
Mazar-e-Sharif might be the only base we would need. I think the airbase is still intact and the good roads leading there are probably defensible.