If the situation in Afghanistan is more or less as it is now, I would promptly request Congress to declare war against the Taliban government. This would be virtually a formality but should have been done after 9/11. This would also grant POW status to most if not all Guantanamo detainees. The present Afghan government would almost certainly negotiate for terms of surrender. Upon the negotiation of terms etc. I would immediately withdraw all U.S. troops. Then I would offer the present government a colony-state treaty.
I would be uncomfortable making such an offer with U.S. troops in country. Once the agreement is in effect and borders determined, I would promptly construct a military base including airstrip and commercial airstrip with military protection. Subsequent colonists would be protected by the military and militias, much like the American frontier. The formula decided upon for economic parity would take effect and Afghanistan would begin a financial climb from the Stone Age into the 21st century. I would secure a legitimate market for the opium and I would anticipate a subsequent diversification in agriculture etc. The Taliban would be neutralized by lack of support as a consequence of economic prosperity.