Plan (at least) one full week for this trip-you´re more likely going to spent two weeks on this tour…
Refueling and Paperwork can take hours-i have spent 7 hours waiting for the only fuel truck that broke down on the way to our helicopter; i have spent 5 hours waiting at the entrance of an airport before finally someone could give me the right stamp to enter (to start Preflight and filing a flight plan)…
Make sure you instruct the handling agent to sort out accommodation next to the airport-you don´t want to lose hours after a long day traveling to the hotel, only to get up 4 hours later again to start at first daylight..
Take your fuel testing kit (kolor kut….).
Make sure you have up-to-date maps, and avoid flying through military airspace (that-most of the time-is NOT on the international maps).
Make sure all licenses are 100% correct and valid-you will be ramp-checked (in some countries) until they find something (they can charge or fine you for)…
Bring enough money and credit cards-some airports don´t accept credit cards for handling or refueling; others don´t accept cash...