After the UN steps in, Afghanistan could easily be back to hellhole status by then.
He won't risk crossing oceans by ship or plane: too many circumstances beyond his control could put our hands on him.
For the same reason, he won't cross a frontier in a car trunk or dressed in a birqa: the shame if captured would diminish his legend.
Best for him is horse travel: if he makes it great, if killed, he retains his glorious warrior image.
I still think what I thought long ago: he is traveling with 5-10 true believers who would gladly jump off a cliff for him. They are in a pre-stocked deep cave with years worth of food, water, clothes, blankets etc. If it's deep enough with a totally hidden entrance and well dispersed vents, it will be invisible even to thermal sensors. He could lay low in such a cave reading his koran for months, easily. Then at the best moment, he slips into Pakistan to appear at his favorite madrassa school, before he disappears into a slum of millions.
The lesson of Somalia (for Osama) is that even the USA could not capture M. F. Aidid in a teeming third world slum.