Perhaps we could learn from the Israeli's experience of plonking new settlements in the middle of nowhere? International law aside, these have been quite successful in terms of providing secure living space for their populous.
Security will of course be paramount regardless of what you end up doing. You will never be able to gaurantee this, as Khan has noted. Maybe we should encourage the Afghans to regard suicide bombers as another of live's inconveniences, along with careless drivers, dodgy kebab vendors etc.