Last minute tour bookings

Tour operators have been impacted by the increase in last minute bookings brought about by mobile technology. Unfortunately, when these just-in-time bookings occur for a tailor-made tour of multiple days in a developing destination, the chance for missteps seems to rise exponentially. Yet more and more often we get requests for a customized tour to begin "this weekend".

If you are working in a remote or exotic environment, where road conditions may change quickly, communication, Internet or electric services may not always be working, visa procedures may by capricious, or you produce tailor-made tours, I would like to hear from you, 

What are some good techniques and technologies that allow you to more easily manage last minute tour requests in a less than optimal environment?